Since, I see that LoPun (I was looking through forums) made an "Overrated video games" list. I thought I can do the opposite. It only makes sense.

Personally, Sin & Punishment, and F-Zero.

I would have to say cave story as well and Dynasty games

Under-rated can be hard to define, but I do think Professor Layton deserves much more appeal - the games are as fun as riding a frozen-over roller-coaster through heck and back.

I gotta say the Need for Speed Underground subseries is quite underrated. The two games got their fame around the time that they were released, but they're still fun as hell to play, and no one's ever really heard of them.

I think james bond night fire for ps2 is really underated ok it doesnt have the best campain ever but it multiplayer is really something to checkout.

It has AI bots, why does no game have AI bots anymore D: sometimes its really fun to destroy an AI instead of your friends, and theres plenty of weapons to choose from and some very well made multiplayer maps.

Thats just my opinion though.

Tokobots on the Psp. while flawed, it's a enjoyable little puzzle/platformer that didn't get the popularity it should've got

I'll have to say Project: Snowblind, Sly Cooper, and Hellgate: London off the top of my head.

Exitebots. If you want an awsome, fast-paced racing game, this is right for you. The twist is, this isn't your ordinary get-first-place racing game, you have to get the most points by doing lots of tricks, thus you could possibly be last and still win. (You get bonus points based on your standing, though.) Plus you can use a Wii Wheel with this game. And did I mention you race with robots based on animals?

And I should get an F-Zero game soon.

Here's some games. I bet Lite can't counter these.
Astal
Vib Ribbon
Magical Popn
Samurai Hero Musashi
and the ENTIRE klonoa franchise.

For me, it'd have to be:

Wild Arms Series (It was always overshadowed by Final Fantasy, so it never got the attention I feel it deserved. It was doomed to moderate obscurity from the start, being considered a 'waiting' game for FF7 right off the bat.)

Digimon World 1 and 3 (Overshadowed by the Pokemon games. While I do feel the Pokemon games are better, the 1st and 3rd games of Digimon World deserve some more recognition I feel. The 1st was an interesting Digimon raising/battle experience, and the 3rd was a decent RPG. The 2nd is pretty bad though.)

Pokemon XD (While Pokemon in general is very popular, this game for some reason went under the radar. I feel it was a unique take at the Pokemon formula, and with a little tweaking, could become a very solid series.)

Jet Force Gemini (I haven't played this one much, but I enjoyed what I did play of it. For some reason, it never took off in popularity. Plus, I absolutely love the soundtrack.)

Bit.Trip Series (Don't know how underrated this game is, but I never hear anyone talking about it, and they should, because all of the games in this series I've played so far are very fun.)

How about...
Pokemon XD and Colosseum: They worked out quite well, and IMO, I have to say they both had the best Pokemon series story ever. Plus the music was kickass, and I LOVE double battles.
Okami: While I've never played it, I've been watching Chuggaaconroy's LP of it, and I have to say it looks pretty awesome!

Other than them, I don't recall any other more underrated games that come to mind.

Do indie games count? If so, then Cortex Command. Probably the most fun I've ever had with a sidescroller, and barely anyone at my school knows about it.

Resident Evil 5 and the Kingdom Hearts series. Those are the only two I can think of at the moment.

You're probably gonna laugh at me for saying, but Crash Bandicoot N-Tranced is pretty underrated I think.

Killing Floor. Why is there hardly any love for SourceMods?

Mafia II deserved a better rating.

and Minecraft deserves more attention.

Probably Rayman 2. That was my favorite game on my Playstation. I never beat it since I don't have a memory card for it >_<

Mirror's Edge

Is every game that comes out around today REQUIRED to have Multiplayer?

Mirrors Edge sucks bawls.
Glover. (Great 3D Platformer.)

Maniac Mansion, this game's just dying for a remake. It seems to only be remembered for the NES version these days.

Deja Vu 1 & 2. Shadowgate is much more well-known, but I really like the theme/setting of Deja Vu much better.

Star Wars for the NES, people say it's bad just because it's not just like the movie, but it's still a really fun game (and it's close enough anyway).

The Lawnmower Man for the Super Nintendo. Unlike the movie, pretty darn good.

I had a lot of fun with those Austin Powers GBC games, they had a lot to do and a really unique menu interface that made it seem like a home computer. You could customize it a whole lot as well.

Hamtaro: Ham-Hams Unite! for the GBC. Not because the gameplay was particularly spectacular, but it was so fun to just run around and explore, great music and abysmally cute graphics.

Since you bring up Star Wars, this reminds me of Rogue Squadron for the N64. It's a much better dogfighter than Star Fox, since you're not on rails and you can explore the maps and uncover extra missions, plus you can choose from several craft. Too bad the sequels kinda sucked.