Personally I'd prefer an XBox, RRODs aren't as common on the new Jasper models, and the online play breaks down to somewhere in the region of $5 a month, hardly bank-breaking. PS3 just hasn't got any games that interest me at the moment, FFXIII was going to be what sold the console for me but now that's coming out on the XB too... and blu-ray? Just spend 1/3 the cash on a BR drive for your PC.
I'm not an xbox fanboy, I just sat down and weighed up all the pros and cons, and even though mine RROD'd about 8 months ago, it was picked up from my house and returned fully repaired for free.
Still... if you like JRPGs it's a very close call between the two, there's some very good ones coming to both consoles in the next 12 months, and if the rumours of Xenosaga 4 turn out to be true I'll be down to my local game store before my PC has a chance to shut down fully.
Just a note - 80gb ps3 is plenty, like L1qu1d said, if you need a bigger drive just grab a huge laptop HDD. If you decide to go Xbox though, get the 120gb. Installing games makes the console considerably quieter and smoother (though there are some games that aren't optimised to run from the HDD so you might want to check out which ones run better and which ones don't. I think GTA IV runs better from the HDD though)