It wasn't for me. I put around 50-60 hours into a PC playthrough, and the only crashes I had were relating to mods I had installed, and were generally fixed just by changing the load order of the mods. I certainly didn't encounter the same level of bugs other people did.
If you fancy it on the PC, I reckon it'll be in the Steam sale at Christmas, so only a month or so to wait for that. It'll give you enough time to play through on the Xbox, then get the GOTY edition on the PC, and then use your knowledge of the game to decide what mods you want to run.
As much as I love Fallout 3 on the Xbox, and as much as I generally prefer console gaming over PC, for me the definitive version of Fallout 3 is on the PC with a few mods installed. It made an already exceptional game even better.
i must be really really slow! 22hours for me and im only up to level 8 and on the fixing the dish mission (which i think is critical?)
does sound like the best plan, maybe i shouldnt try to do everything in one run? (though i do like to)