I've been spending a lot of time playing GBA games on my DS. I hadn't touched my SP in months, so I had plenty of catching up to do, and I'm really enjoying how they look and sound.
Back on topic though, so far, the only DS games I've played are SM64, Urban Asphault, and Mr. Driller.
SM64 I'm really enjoying (having never played it on the N64 though). The minigames are pretty fun, and I like that I can just pick up the DS and play for 10-20 minutes without worrying about finding a place to save my game. I don't know if the actual missions are changed from SM64, but they also play through fairly quickly (less than 20 minutes each, at least so far). This is exactly how I like to play my games (in very short spurts), so it fits me very well. I don't use the sylus, finding the d-pad and buttons to be a superior control scheme.
Urban Asphault is another game I can play for 10-20 minutes, and actually feel like i"m making progress. Basically, you start out with just a couple of races available to you at the start and 1 car. As you win race series (usually 3 races using a specific car type), you'll unlock more cars, upgrades, or races. Even if you don't win the race, you can win some cash, which can be used to upgrade your car in a multitude of ways (tires, suspension, weight reduction, etc). The differences after upgrading are small but noticable, and definately contributed to my getting past some races I had trouble with before.
The different car classes also feel quite different. The hummer feels slow and unwieldy. The 350Z is fast and nimble (but slides around more, especially before you upgrade your tires). My only complaint would have to be that the track selection is fairly limited, so you get to know & memorize the tracks pretty quickly. I love racing games of this type (I'd say its like a mini-PGR..not on that same level, but a similar idea), and I'm having a blast with this one.
Mr. Driller I picked up just this week. I had wanted to pick it up with the DS, but couldn't find it anywhere. Now it seems its back in stock in most places. It is supposedly similar to previous games in the series, though I never played those either. The goal here is drill down to a certain depth to beat the mission (300M for example). If you drill below a block, it will fall until it either finds another block of its color adjacent to it, or it squishes you. If 4 blocks of the same color are connected, they'll disappear and the ones above will drop, etc. Complicating matters is an air tank that slowly depletes unless you pick up air capsules to replenish it (these are scattered around as you drill down), and blocks that will consume air if you drill them (they're easy to tell apart). The game has quite an addictive quality, and although I had no idea what I was doing, strategy-wise, when I started, as I played a bit more, I could see that it definately did involve some strategy to get to the air capsules that were completely surrounded by air-depleting bricks. And as you advance to the higher levels, most air capsules fall into that situation.
As I said, I've only had this one a couple of days, but I think it's one of those games I'll keep coming back to. It definately gets hard fast though. 300M wasn't too hard. 500M was challenging (it's not just the depth that changes, how the bricks and air capsules are placed also gets more difficult). On the 800M map, I'm having a devil of a time just trying to get past about 350M..so that's where I'm at now.
I know Zookeeper is also exactly my type of game, but until the price drops on that one I'm going to wait. ($40 is a bit much for a bejeweled clone -- I doubt it'll stay at that price point, especially when every review so far has stated it should probably be about $20).
As there are only a limited number of DS games out, you might just want to check out GameFaqs forums for each and see how they've been received. Yeah, the noise / content ratio is a bit high, but you can get some decent info if you filter it.
I noticed a couple of posts about the Urbz having some kind of game-stopping bug, but to be honest, I wasn't interested in the game, so I didn't read further. You might want to check that.
[edit to add:] Just went through the forum again, and although there are numerous reports of 'glitches', it doesn't look like any game-breakers..sorry to raise a false-alarm there.