I have the collectors edition of Halo 2 and I honestly can't tell you if it's much better than the regular edition --- it comes with a second disc which is a DVD that can be played in a DVD player rather than only in an Xbox --- I have never touched the disc --- was always way too busy playing Halo 2
The case for the collectors edition is really cool, though. The game disc is exactly the same, but I'm not positive if it has a different image on it (to be honest, I don't think it does, but Halo 3 legendary edition does have a different image on the cd than Halo 3 regular edition, I know that for a fact)
On Xbox two good party games are Fuzion Frenzy and Kung Fu Chaos --- these games probably both got awful reviews but they are somewhat fun --- Fuzion Frenzy is especially fun after you have seen the travesty that is Fuzion Frenzy 2 on Xbox 360.
XIII is an interesting cell shaded shooting game --- it was great (I never beat it but got pretty far)
Tony Hawk Pro Skater 2X - Fun game --- if you have ever played THPS2 on PSX, this game is actually a nice step up with graphics --- they made the graphics look really nice for the Xbox version --- this Xbox version has a few extra levels but they are awful. It has everything from the Playstation version (as far as I know) so no worries.
Another good shooting game is Kill.Switch - a lot of the game is centered around a cover system (if I remember correct) which works out good.
Both of the Gauntlet games - they are fun --- not sure about multiplayer, I think both support 4 players --- if they do, these would be good party games.
My friend liked the Prince of Persia games --- I got stuck on an early puzzle in one of them and gave up --- they seemed cool.
I like Rainbow Six Vegas and GRAW on Xbox 360 so I am interested in playing the older Rainbow Six games on the original Xbox - there are a few - I personally had "Black Arrow" and it was good, but I think it's more of a multiplayer game --- single player might be cool too though because I know R6V and GRAW had pretty good campaigns (never played Black Arrow campaign, if it even has one).
Burnout --- I think Burnout 2 and 3 exist on Xbox --- they were a lot of fun -- whatever you do, don't get the first one though because if I remember correctly it was pretty awful.
Unreal Championship - the first one - but sadly, this is another one that you kind of have to play online for the full experience --- I don't really know how well it would be offline --- you can of course still play using system link (tunnel over XBConnect or XLink) but nobody really plays it anymore =( I don't care for the sequel at all.
Breakdown - this is one of the most overlooked games (I believe?) --- it's really awesome and pretty scary --- you know how in games you normally "Hold X" or something to pick something up and it instantly appears in your inventory or whatever --- this game you actually see from a first person perspective that action, so you pick up magazines for your gun, take bites of burgers and gulps of soda... it's FREAKY but the storyline is top notch. I got really far in this game and then got stuck at a boss type character.
Deathrow - it's like a combination of frisbee and basketball (strange, I know) - you get to wind up the frisbee and hit the opposing team with it to knock the players out --- you can also fight to knock people down --- *turn off the player voices if you don't want to hear swear words - you can play this on system link (possibly 2+ player split screen, I believe
The GTA games were decent on Xbox --- I didn't care much for San Andreas (some say this is the best GTA ever?) but GTA 3 and Vice City were decent games
Mechassault - I'm not into mechs but I loved this game. Story was decent - the best part was multiplayer on xbox live which sadly no longer exists. You can still play system link over xlink/xbconnect if you can find someone to arrange a match with (played this for hours on end back when the game first came out... LOT of fun)
Lot of people like Fable (lost chapters edition? maybe that's the only one that exists for Xbox, I'm not sure) - I played a bit of it and thought it was interesting, got stuck though. I played Fable 2 on Xbox 360 and beat it multiple times, I love it... Fable 3 not so much. Some do say Fable 1 is the best, though.
That's all I can remember right now.