To improve the vanilla game, absolutely not. To fix most bugs not covered in the last patch, use this fixpack. Do NOT use Dudley Fix. A *massive* difference to vanilla: your game will be completely overpowered, with spells/abilities/items etc. that simply have no place in BG1. That's not surprising, since most 'must have' lists are generally arbitrary on personal preference. Actually, your PC's 6:4 aspect is precisely what the game runs in natively, so you should NOT use the widescreen mod at all, especially if you do use the BG2 engine (simply change to that resolution in game), or if you choose to use the widescreen mod (not recommended for vanilla BG1), then choose your native resolution.

Precisely what I needed! Thanks friend!

For the original BG, there are really only two--Baldurdash and Dudleyville. Both are fairly dated at this point, and both include "fixes" that I would personally consider content changes or tweaks. If I had to recommend one, it would eb Baldurdash. While there was a modern fixpack project started for the original BG (in the same vein as BG2 Fixpack), it never reached a release.

One of the best sources of fixes for BG bugs is actually BGT. Ascension and the BGT team identified and fixed a good number of original bugs during their porting process. Ascension was also nice enough to work with Beamdog to make sure these all found their way into BGEE.

The drawback of BGEE and BGT is, as Hickory mentions, that BG in the BG2 engine (be it via Tutu, BGT, or BGEE) involves a lot more changes than just bug fixes. I happen to think the BG2 engine provides more advantages (even without the additional bug fixes), but YMMV, so read up on it first so you can make an informed decision.