Do not, I repeat do not, ever play Fallout 2 without the patch
installed. I tried it out once, because I was interested in the
differences. I gave it up when I lost the front end of my car,
leaving me just with the trunk. Some other fixes:
Boxing in New Reno will no longer lock up the computer.
The Dice Game will give you winnings.
The Lloyd quest in New Reno will not lock the computer.
Talking to Tandi about the Vault 15 quest will not lock
the computer.
Loading and Saving of Save Games have been sped up.
Party members will not turn hostile (under most circumstances)
any longer, so you will be able to talk to them all the time.
Ghouls in Gecko will not randomly shoot at you.
Harold will give you the right information when you are trying
to optimize the power plant.
Shopkeepers will get money more often - this is more of a tweak
then a bug fix.
Unpatched version savegames are incompatible with the patched version,
if you patch the game later, you'll have to start anew. There is a third
party savegame converter, which, however, I have never tested.