I now have an Origional X-Box, and im unsure what games to get.  Ive alrady got Halo2 and Fable, plus the Forza and PGR that came in the pack, however i want a couple more games to play around with.  

Age isnt important really, just as long as they play well.  Ive already got Oddworld on the shopping list, but i think 3 or 4 more should fill the collection out nicely for a  month or two.  

Psychonauts!, Beyond Good & Evil

GTA SA is excellent on the xbox, so are all the Burnout games and Rainbow Six 3.

One of my favs is Full Spectrum Warrior.

I bought an original xbox at the begining of the month and so far Ive got a few games for it other than the original 4 youve already got.

Mechassault
Mechassault 2
Area 51
and
[Destroy All Humans

Ive mainly played Fable so far though, but I have had a quick try of all those games and they seem good, might have to see about Beyond Good & Evil too.