For what it's worth, I have listed the games I own in the order I would sugest buying them. For me they have all been worthwhile purchases and I don't feel that any are really bad games.
Super Mario Sunshine
Super Monkey Ball
Resident Evil
Rogue Leader
Eternal Darkness
Wave Race
Luigis Mansion
Burnout
Mario goes without saying and is eating up nearly all of my game playing time at the moment. The only time I am playing games and it is not SMS, is when I am playing Bubble Bobble on the GBA
Super Monkey Ball runs Mario a close 2nd (I am awaiting SMB2, which is in the post from DVD Box Office). This is one maddeningly addictive game and one which I return to often.
Resident Evil comes in 3rd, thoroughly enjoyed it and prefer it to Eternal Darkness in the survival horror stakes. I found that ED, while having a superb story, was a little too easy to complete. Resi offers more challenge, especially on the harder level which becomes available after completing it. I also prefer the overall atmosphere of Resi.
Splitting the 2 horrors, I have placed Rogue Leader. I never played the original and being a big Star Wars fan, I love the atmosphere of the whole game. It is a lasting challenge and I still go back to it attempting to get all the gold medals.
Next up comes Wave Race. I never played the N64 version so any negatives about it being too similar fall on deaf ears here, it plays really well and is good fun. I have yet to complete it and haven't really given it as much time as I would have liked. Damn that Super Monkey Ball
Luigis Mansion fills the not quite bottom position. It is a lovely little game, which was a lot of fun to complete. The 2 problems with it were that it was too short and within that short time, I never really felt in danger of reaching game over. It is not one to challenge any experienced players out there, but it is certainly worth a look.
Burnout is sitting in bottom position at the moment and I still enjoy playing that one too. Got up to the last championship and done a few of the head to heads. It is another that hasn't had the play it deserves, again due to SMB.
I have played other games round friends and found Pikmin to be a lot of fun and that is a title that will get a purchase from me one day. Super Smash Brothers on the other hand, will definately not be getting a purchase. We played that for some time in multiplayer and it bored me silly. Having said that my friends liked it, so I guess it is to each his own.