I guess I will toss out my suggestions, as I too wanted to add more of a Fallout feel to my game through mods, and I think I have done a reasonable job at such. I'll give you my LO as well, so you can take a peek at that if you like as well, but I will give my main suggestions with some links:
First and foremost, I recommend http://fallout3nexus.com/downloads/file.php?id=2761 and http://fallout3nexus.com/downloads/file.php?id=3211 are both absolutely essential to my build, though even if I don't use it myself, you may also want to take a look at http://fallout3nexus.com/downloads/file.php?id=7565 as a possible choice in place of FWE, as it is similar but does have a different approach to how it does some things. Of course, if you do decide to run with FWE+MMM, you will certainly want to look into the http://fallout3nexus.com/downloads/file.php?id=4968 options available as well to patch some things together nice (and will also be needed for another recommendation I have). Finally, I also want to give my backing for http://fallout3nexus.com/downloads/file.php?id=1409 as well - great selection of Perks, many in a Trait style fashion.
That all being said, you may also want to take a look into http://fallout3nexus.com/downloads/file.php?id=3388 to get a little more flavor out of the weapons in the game (this will again need FOIP) - which you might as well do since it is still an FPS with RPG mixed in, so enhancing that aspect will help the levels of enjoyment (and add some old school aspects back).
Then, to get the companions to act a little more like the old Fallout games (with some new features to compensate for the FPS aspects of the game), I would take a look a http://fallout3nexus.com/downloads/file.php?id=1925. You can't use Followers Enhanced from FWE with it, but would use it in place of that. Also, it looks like the author may be getting some more updates done on it, so that may be something to look forward to. This will at least make a few more NPCs have a little character to them.
Also in the realm of NPCs, you could look at http://fallout3nexus.com/downloads/file.php?id=6044 which will add some more NPCs out and about. Most are generic as hell still, but there are some special events added in like escorting groups to locations for money, or getting robbed and having to chase the thief down for your goods.
Next there is the newer mod, http://fallout3nexus.com/downloads/file.php?id=15881, which will add some meaning back to the Action Point system of the game and make things a little more like the older games in regards to that. It is listed as Alpha, but it works fine, it is just still being actively worked and more features being considered. Perfectly stable though and works a charm.
To get a little more investigative life back in the game you could take a look at both http://fallout3nexus.com/downloads/file.php?id=5573 and http://fallout3nexus.com/downloads/file.php?id=13064 (this one will need the assets from http://fallout3nexus.com/downloads/file.php?id=4736). While you are at it, maybe take a look at http://fallout3nexus.com/downloads/file.php?id=14368 to make some use out of the random cars and rubble piles about the wasteland.
Those cover a fairly good chunk of Fallout originals that should spice your game up. Might also be worth checking out the UI patch linked in my signature to mix the more PC friendly DUI interface with a Fallout classic feel laced in (also works with other HUD mods and DUI is also patched up to work with FWE).
And then, last but not least, my current LO for you to peek at (at least I think this is the correct one, should be darn close):
Spoiler Active Mod Files:00 Fallout3.esm01 Anchorage.esm02 ThePitt.esm03 StreetLights.esm04 BrokenSteel.esm05 PointLookout.esm06 Zeta.esm07 FNNsys.esm08 Destruction.esm09 Phalanx-PointLookout-Navmesh.esm0A aHUD.esm0B iHUD.esm0C CRAFT.esm0D CALIBR.esm [Version 1.4]0E Mothership Crew.esm0F FO3 Wanderers Edition - Main File.esm10 Mart's Mutant Mod.esm11 FNNIguana.esm12 Enhanced Weather - Rain and Snow.esm13 Xepha's Dynamic Weather.esm14 DCInteriors_ComboEdition.esm15 FNNCQ.esm16 FNNCQ_DavidsLab.esm17 FireLightFix.esp18 BlackWidowBurkeFix.esp19 LessRocks.esp++ Reduced Dust Particles.esp1A DarNifiedUIF3.esp1B Selective Fire.esp1C DynamicCrosshair.esp1D Stimpak Counter.esp1E CASM.esp1F Princess Better Prompts v1pt1.esp20 Agatha Radio Enhanced.esp21 Enclave Radio Enhanced.esp22 GNR Enhanced.esp++ GeneratorSound.esp23 ReneersRadioMod.esp24 UPP - Pack 1.esp25 UPP - Pack 2.esp26 UPP - Experience Perks.esp27 UPP - Quest Perks.esp28 Ex Libris - PreWar Book Titles.esp29 implants.esp++ Tenpenny Tower true peace.esp2A Scavenger World.esp2B RZW_SimpleGrab.esp++ LittleLamplightDogs.esp2C ReciveLyonsPA.esp2D RZW_PortableLamps.esp2E MAXdog.esp2F MegatonHouseExtraStorageSG.esp30 loadingsc.esp31 Treasure Maps_Underground.esp32 Treasure Maps_Secrets of the Wasteland.esp33 Treasure Maps_Bobblehead Edition.esp34 Treasure Maps_A Fist Full of Caps.esp++ Destruction - Main.esp35 Destruction - Main - Statics.esp++ Destruction - DLC.esp36 Destruction - DLC - Statics.esp37 BusworldV1.05d.esp38 NoKnockedOverComments.esp39 SneakModeEffect.esp3A NPC Height Randomizer Less Variance.esp3B CrowdedCities_v2.esp3C MTC Wasteland Travellers.esp3D MTC MoreGuardsInBigTown.esp++ Clothed American Soldiers.esp3E Confessor Cromwell has a Break_EV.esp3F Clothed Sarah Lyons - Sleepwear.esp40 Outcast Scribes03.esp41 ThreeDogs 3 Dogs Alternative.esp42 NPC Response Expansion.esp43 FruitTrees.esp44 RandomExtraTraps.esp45 megalight.esp46 Riverboat Landing Merchant.esp47 FO3 Wanderers Edition - Main File.esp48 FO3 Wanderers Edition - DLC Anchorage.esp49 FO3 Wanderers Edition - DLC The Pitt.esp4A FO3 Wanderers Edition - DLC Broken Steel.esp4B FO3 Wanderers Edition - DLC Point Lookout.esp4C FO3 Wanderers Edition - DLC Mothership Zeta.esp4D FO3 Wanderers Edition - Alternate Travel.esp4E DLM_FWE Medic PA FWE+Zeta required.esp [Version 1.0]4F MZC-FWE_CP.esp50 Refurbishes [ALL].esp51 WeaponModKits.esp52 WeaponModKits - FWE Master Release.esp53 WeaponModKits - OperationAnchorage.esp54 WeaponModKits - ThePitt.esp55 WeaponModKits - BrokenSteel.esp56 WeaponModKits - PointLookout.esp57 WeaponModKits - Zeta.esp++ Echo_UseBothGloves.esp58 Ammo Press Calibrified.esp59 BBBackpacks-v1-1.esp5A AutoGates.esp5B Burnification.esp5C BuildableBots v0.3a.esp5D WSG Improved.esp5E ImmersiveHealth.esp5F FalloutFood.esp++ FalloutFoods - FWE Master Release.esp60 Mart's Mutant Mod.esp61 Mart's Mutant Mod - DLC Anchorage.esp62 Mart's Mutant Mod - DLC The Pitt.esp63 Mart's Mutant Mod - DLC Broken Steel.esp++ Mart's Mutant Mod - DLC Point Lookout.esp64 Mart's Mutant Mod - DLC Zeta.esp65 Mart's Mutant Mod - FWE Master Release.esp++ Mart's Mutant Mod - FWE Master Release + DLCs.esp66 WRWC - Classic Fallout.esp67 Attentater's Wasteland Economy.esp68 FleshBurningPlasma.esp69 Gifts4Kids.esp6A ShellRain.esp6B SunGlassesFX.esp6C yaDisguisesMod.esp6D yaDisguisesMod-DLC-Anchorage.esp6E yaDisguisesMod-DLC-BrokenSteel.esp6F yaDisguisesMod-DLC-ThePitt.esp70 yaDisguisesMod-MOD-FWE.esp71 Savage Wasteland - Fewer Gun Wielding Maniacs.esp72 Phalanx-MainFollowerModule.esp73 Phalanx-BrokenSteel-Integration.esp74 Phalanx-PointLookout-Integration.esp++ MrSlackPants-DecentPipBoyLight.esp75 ZZ_APP.esp [Version 0.21]76 Enhanced Weather - Weather Sounds in Interiors.esp77 Realistic Interior Lighting.esp78 Realistic Interior Lighting - BS.esp79 Realistic Interior Lighting - OA.esp7A Realistic Interior Lighting - PL.esp7B NColorDCInteriors.esp7C Xepha's Dynamic Weather - Main.esp7D Xepha's Dynamic Weather - Anchorage.esp7E Xepha's Dynamic Weather - The Pitt.esp7F Xepha's Dynamic Weather - Broken Steel.esp80 Xepha's Dynamic Weather - Point Lookout.esp81 Xepha's Dynamic Weather - Rain.esp82 Xepha's Dynamic Weather - Sandstorm.esp83 Xepha's Dynamic Weather - Dynamic Sneak Bonus.esp84 Xepha's Dynamic Weather - Green Tint Remover.esp++ FNNIguana - FWE.esp85 FNNIguana - MMMRC6.esp++ FNNsys - FWE.esp86 FNNsys start inventory.esp87 Bashed Patch, 0.esp