Orius
Unrepentant DM Supremacist
Do you have a copy of JG First Fantasy Campaign? Arneson had a system for awarding XP based on gold and treasure spent in seven areas of interest: wine, women, song, wealth hoarded (xp lost if stolen/spent), fame, religion/spiritualism, and hobby. Each PC could have one or more areas of interest, and spending treasure on a category would result in a % of the total value, depending on the category's relative importance to the PC.
That's an interesting idea.
Generally I wouldn't run the original rules myself; it requires too many judgement calls on the part of the DM, and I'd probably end up drawing on my experiences from later editions of the game to the point where I might as well just play said editions. Also, since the original books were disigned for use with stuff like Chainmail, which I certainly don't have, they're like an incomplete game to me. These sorts of things are what led to the creation of AD&D and the Basic game, after all.
However, I like that XP idea. The one thing about 3e that bothered me the most was that XP advancement always felt a bit too fast. And that made it harder to really run the old mega-dungeon and stuff like that properly. However, the 3e XP tables are set up in a way that to me makes stuff like awarding XP in a non-standard way easier than in previous editions. It's a lot easier to figure out how much XP to reward on the fly when everyone needs level X 1000 XP to level up, certainly easier than when the XP is split across 6 different tables. Anyway, I was considering switching to a system that awards the players based on how much got accomplished during a game session, and Arneson's areas of interest could add an interesting twist to awarding XP like that. The downside is that players who are less into in-depth RPing could end up feeling left out, since XP awards like this come close to RP awards in some ways.