LOL.
I reckon you should just say how much you are willing to spend on a PC. The P4 still has a lead in Video encoding, and dispite what people say, it's about a 20% difference compared to a Athlon 64. For raw CPU computational power, the Athlon has the edge by a lot. As for people saying that the Athlon 64 has equal or near equal multitasking power than a P4, that's rubbish. Have you ever played Halflife 2 while encoding a 1GB wave file to MP3 and still getting 30FPS on an A64? Nope. A comparison between the 2 was done (can't remember the link, it's on an older thread) and the Athlon 64 stuck at about 7-9 FPS. In saying that though, when they was no multitasking being done, the Athlon wiped the floor with the P4.
If money is no option, and it's not for gaming, then there is not much in it between the two. Also, the P4 has features that are currently not being used as of yet, so things can only get better for it. Really, there is no difference between the two in my eyes, but if you have the money, It think that the P4 6xx series (Only the 6xx series) would be the better buy.
I'll see if I can find that benchmark sometime if anyone requests it.
As for going near a G5, god I wouldn't touch it. Apple adverts were band in the UK because of the unfair testing when they compared them to PC alternatives. Once they were independantly tested, things got interesting and the Athlon FX55 and the P4 EE wiped the floor with the Dual G5 in most things. The Duel Xeon and Opteron knocked it out into space. Don't touch.
Well, that's my 2p.
C ya!