Spell Mods: http://www.tesnexus.com/downloads/file.php?id=12466 and/or http://www.tesnexus.com/downloads/file.php?id=9562
Also consider my http://www.tesnexus.com/downloads/file.php?id=34735 mod. It is of course not a spell mod, but it allows you to do the following with spells:
1. Have one bound to a hotkey as an Auto Cast spell. When tapping the hotkey, the spell is cast directly without becoming selected (thus letting you keep your attack spell of choice selected). Great for defensive spells or conjuration spells.
2. Have multiple spells bound to one hotkey as Multicast. Same as above, except that all of the spells are cast in sequence, still without chancing you current spell. You can add a restore health (or any other) multiple times to such a hotkey, which will make it being cast multiple times by one tap
3. Have multiple spells bound to one hotkey as a cycler. One tap of the hotkey selects the first spell, the second tap the second, and so on.
The mod also lets you have up to 40 (instead of the vanilla 8) hotkeys, including mouse buttons - and multiple "wheels" selected by modifier keys for a possible total of 160 hotkeys, and of course have similar treatment of non-spell items.
Realism Mods: Look up Real Hunger, Real Thirst and Real Sleep on the Nexus.
Make sure to grab the OBSE versions of RH and RT, and the Extended version of RS.
As for anything else you might want - IMHO, I could play without many mods that I like, but I could really not play without a number of the Gameplay tweak mods - mods that enhance the gameplay or user interface or both. Mods like:
Realistic Leveling (though nGCD or Oblivion XP are good alternatives) - makes the leveling natural and sound, and not the gamey concept it is now
Realistc Fatigue - makes encumbrance and fatigue really matters
Progress - let you easily control the speed of skill leveling
Togglable Quantity Prompt (updated version) - let you sell a single item or all items of a stack, without having to select amount or confirming the trade for each transaction
Darnified UI - makes the user interface look good
Really AEVWD + TES4LODGen - makes distant houses, ruins, forts, etc. visible from afar, instead of just popping up from nowhere when you get near. Unlike the others, it must be used with caution since a full install may mangle your framerate
...and some of my own, like:
Map Marker Overhaul - lets you add tags like [done], [strong enemy] or whatever you want to map markers, lets you add your own freely named markers wherever you want, and lots of other things.
Enhanced Economy - makes the economic game a bit more immersive and interesting and lets you control how fast you become rich
HUD Status Bars - adds a few more interesting status bars (like weapon charge for enchanted weapons, a correct encumbrance bar, etc.) and lets you easily add new bars for whatever you want
Display Stats - makes the small popup that displays things like armor rating or weapon damage, also display all the hidden stats
Soulgem Magic - either prevents large soulgems from accepting small souls, or lets a large soulgem accept multiple small souls to eventually become one large - to avoid vasting a large soulgem when you kill a rat
Follow the link in my signature for easy access to my mods...