I'm just posting to say that the problem around which this topic revolves is soon to be remedied; I finally bought BG1 and BG2! I picked up the holiday Dungeons & Dragons bundle a few days ago, and am now a proud owner of so many fantastic games! =D
I know a lot of others prefer BG1 in BGT or Tutu, but I'll come from the other side. Play the games unmodded (except for fix packs and a few tweaks) before going combined. BG1 may be the original (and most limited) of the games, but it has an atmosphere all its own on its own that can't be found in Tutu or BGT.
In my opinion...
My last couple play throughs I've done BGTuTu and enjoyed it, but it definitely can become a bit unbalanced. There are a few things that BGTuTu adds in that I find hard to live withouth
1) engine speed. BG2 is just faster, which means it takes less time for you to explore an area, get from point A to point B, etc. (there may be a way to change this in the ini file for BG1, but I can't remember)
2) Containers - Scroll Cases, Gem Bags, Etc., there are just too many of those items you come across if you don't have the containers to store them
3) the Tab key. Given the vast number of barrels, chests, etc. that are just background and not actual containers, it's a real pain to hover over each one to find stuff. Love hitting tab and seeing everything I need to check into.