Sonic Advance
It's a solid Sonic title which reminds me of the original Sonic The Hedgehog game. It's a little on the slow side but it's okay, I approve of this game as a quality Sonic title.
Sonic Advance 2
This is the game where the whole "hold right" thing really came into play but even so it's still a good Sonic game. It was much faster than Sonic Advance though I prefer the original Sonic Advance slightly, once again a good entry in the series.
Sonic Advance 3
This is everything the 3rd entry in a series should be, it takes the the best aspects of the first two games and adds a little of it's own flavour (Tag team) to create the best in the series. The stages are the perfect blend of run fast with platforming elements and overall it's easily the best in the Advance series. In fact it's one of the best Sonic games ever in my opinion.
Sonic Battle
This game turned out better than I thought though I wouldn't call it amazing or anything. It's a Sonic fighting game with some cool ideas but I feel it's the limitations of the GBA that hold it back from being better. Single player story was pretty fun but the best part was a robot called Emerl.
It's basically like create a character except your picking out his moves rather than his visual appearance, I had fun collecting the cards or whatever it was that got you new moves.
Decent game, not a bad one and it's not a shameful title to own in your collection, probably the best Sonic spin off title.
Sonic Rush
An awesome game with an even better soundtrack which plays like a Sonic game turned up to 11. This is your typical 2D Sonic game but has a streamlined level design to allow you to blow through them at amazing speeds. The dual screens are used to give you a bigger view of the action and it works really well, it makes New Super Mario Bros look lazy for having one of the screens just for displaying useless information.
You either like it or hate it, personally I love it and I'm glad it plays differently to the classic/Advance Sonic games.
Sonic Rush Adventure
I wrote a review for this one recently so if you want to check out my opinion head on over to
http://www.destructoid.com/blogs/Xavier/late-review-sonic-rush-adventure-56124.phtml
(Sorry some of the images are missing and I'm not bothered about updating it)
Personally speaking I'm a fan of good Sonic games no matter where or when they came out. I'm not one of the people who believes the only good Sonic games were on MegaDrive/Genesis/Sega CD nor am I one of those new Sonic fans who thinks 3D Sonic games (In particular Sonic Adventure 2) are awesome and Shadow is the best thing to happen to Sonic.
If your a true Sonic fan then these are the games you should already own or have plans to own at some point. Don't get too worked up guys, it's just my opinion.
Sonic The Hedgehog 1/2/3/& Knuckles
Sonic CD
Sonic the Hedgehog Pocket Adventure
Sonic Advance 1/2/3
Sonic Rush/Adventure
My recommendation is if you are looking for good Sonic games these days stick to the stuff that appears on Nintendo handhelds. This Sonic game from Bioware has me worried, the thought of Bioware doing an RPG for the Nintendo DS is great but the fact it's a SONIC based on is my problem with it.
It reminds me of Mario & Sonic At The Olympic Games, that might as well of been Mii At The Olympic Games.
Bioware can have the spin dash as an attack, add in a Green Hill remix and thrown in a storyline involving falling in love with humans (Sonic 2006 style) but I doubt they'll convince me that the addition of the Sonic universe was a good one other than to sell more copies of this game.
Don't worry Sonic I'm still a fan, even if your good games are few & far in between,