I really dont want to get into this, but comments like:
It only has a 733MHz chip, my pc is faster!
Are nonsense.
I think PS2's are clocked at under 300Mhz, dreamcasts are only about 200mhz but they perform ALOT better than similar clocked PC. Pentium 200 or Dreamcast? No contest. Now you have 733Mhz with the xbox, stacks more memory, HUGE bandwidth and geforce graphics.
Add on the extra overhead of an emulator, an xbox emulator on a pc would absolutely choke. I would like to see GT3 running full speed at the same level of detail as the ps2 version.
Xbox and PC may share some common parts but their architecture is chalk and cheese. I haven't looked into the Xbox's specs for a while but it will be a LONG time before pc's catch up, some people say 2-3 years +.
In short, PC's are not designed to handle large amounts of data (textures etc.) They are designed to push lots of code acting on relatively little data (spreadsheets etc.)
A pc may have a gf3 (which is a beast

) but it also has all the other age old pc components/architecture slowing it down. When pc architecture was first devised do you think they intended huge amounts of textures to be shuffled around inside...no. They have attempted to fix this with the addition of the agp bus.
My personal opinion is PC's aren't even up with PS2's yet (look at GT3) and the XBox is a big leap over ps2.
Bottom line is, so the pc catches up with the xbox in several years, by that time another super console will be released upping the ante one more time. There is room in the market for mega $$$ mega quick consoles, PS2 proved that. I think PC gaming has taken a permanent back seat to the new consoles, in terms of raw power anyway (which doesn't make the game I know)