what distance are you sitting from the screen? I also have a 42' panasonic plasma 1080p but play Oblivion at 720p because at that distance ( 3.5 meters approximately ) you don't even notice a difference, it would take a 50+ screen to notice
definitely go with Redimized, looks just as good with half the VRAM usage. even if you have 2 gigs as I do, there's no reason to stress the system more without a very good reason ( as you add mods you'll soon notice the real bottleneck is not your hardware, but the crappy, unoptimized, rushed, you name it, game engine. that's why both Fallout 3 and Skyrim run a lot better )
other great texture replacers to go alongside with QTP3:
get CorePC's vibrant textures, and install them BEFORE QTP3 so that they get overwritten by it. reason, they include some stuff that QTP3 doesn't ( trees, grass, sky, oblivion realms )
be sure to get this after qtp3, it makes a big difference : http://oblivion.nexusmods.com/mods/26756 and this while you're at it http://oblivion.nexusmods.com/mods/31595
( somebody posted a fix for the pixelated fort floor not long ago, but it's on mediafire and I can't find it
) if you want it you could PM me and I can email it, or maybe that somebody will post the link again if you're lucky
other good stuff:
diverse grasses is cool, I'd also get RPGblackdragon's trees ( they look awesome ) and his lowtripolygrass ( short-long version type 1, more variety AND improves fps in grassy areas, no reason not to use it imho )
Mythic textures series ( mythic creatures, mythic animals etc. )
Oblivion Hires textures
check TOTO ( oblivion texture overhaul ) http://devnull.sweetdanger.net/obliviontextureoverhaul.html for some more goodies
Improved Sky Texture by Xerus
Brumbek's Sky Pack
Mikal's textures!! improved doors and flora, improved trees and flora 1 and 2 ( love em )
enhanced vegetation, and xtudo's darker trunks fix
Xerus' distant land textures.
Unique Signs.
optimized distantland max 50% could save you a couple FPS with no visual difference. install after UOP and before UL.
I'll post others if they come to mind.
if you can be bothered to learn how to use it, MPGUI + TES4LL + TES4QLOD will allow you to generate awesome looking distant land meshes and textures.
about OBGE, it's definitely a must-have. Liquid Water looks glorious and it actually runs way better than vanilla water with their performance-killing reflections.
it also gives you way better anisotropic filtering and antialiasing than you can force through drivers, and if you've got a killer GPU ambient occlusion and indirect ligthing will make the game look photorealistic ( I wish I had that kind of horsepower O.O )