Really this hits it right on the head. While some people prefer the gameplay of Fallout 2 it is, at it's core, the same game. The only major differences are more for comfort than anything (i.e. being able to move more than 999 caps at a time, or easier outfitting of NPCs). You would really be missing out on a lot of the greatness of the Fallout series if you skipped the first game. While I probably replay Fallout 2 more than I do Fallout, the first is a game that I will always remember story wise. It just sets the stage so perfectly for the second game.
Either way if you are a fan of RPGs you will probably end up buying both, but I would say if you could only play one of them you are much better off playing the first. Hope this helps.