There are about 20 more titles on my Dr.Wily radar. I absolutely LOVE this little White box of whimsical wonders.
I'm holding off right now though until i finish 8 more titles in my collection. I'm already overwhelmed as it is!
Of the 20, the list includes Resident Evil: Darkside Chronicles, Mario Kart Wii(I STILL don't own this), Dewy's Adventure, Boom Blox, Epic Micky, Metroid: Other M ect ect.

Just got a batch of WiiWare games (look up WiiWare forum for the list).

For Wii I hope to get good deals on a few missing titles:
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• Mario Party 9 (these 2 to have all Mario games)
• Mario & Sonic at the London 2012 Olympic Games
  .
• Sonic and the Secret Rings (these 3 to have all Sonic games)
• Sonic and the Black Knight
• Sonic Zero Gravity Riders
  .
• Tetris Party Deluxe (these 4 to have all Nintendo-published titles)
• PokéPark Wii: Pikachu's Adventure
• PokéPark 2: Dimension Beyond
• Go Vacation
  .
• A Boy And His Blob (other Wii games probably worthy to add)
• Back To The Future
• Boom Blox
• Boom Blox: Bash Party
• deBlob 2
• Ghost Squad
• Impossible Mission
• Klonoa
• Mortal Kombat Armageddon
• The Kore Gang
• The Munchables

They actually released Impossible Mission on Wii? Shows what I know.

I got the Black Knight yesterday... haven't had the time to play it yet (instead, I wrote an impressions/review post on Speed Racer), but the controls in the Secret Rings felt... stoopid. (I'm more or less working with the goal of getting all Wii Sonic disc releases, too... except the crossovers with Mario.)

Boom Blox: Bash Party is one of the best party games I can think of on Wii (haven't tried out Boom Blox yet). Klonoa too short, Munchables maybe a bit too simple/unchallenging, Ghost Squad a decent on-rails shooter, Go Vacation I haven't played that much but 'Jack of all trades, master of none' might be an apt description... too bad about the racing and the cheerleading minigames.

Boom Blox was fantastic and one of the few games that utilized the Wiimote right. God I miss that game...

I hear that game is already predicted to be a future rare game that hardcore collectors will probably fight over. (though the game didn't exactly have the most enticing premise. I think one of the first results for reviews on youtube answered the question "why not go outside and do some real walking?" Their answer: maybe you live in a place with too much snow... or volcanoes and deadly magic dragons. )

@WaveBoy: Dewy's Adventure, you say? I remember when I got mine. It was from the Best Buy clearance rack. It was like "choose any 5 games for $25", Dewy was literally the only game on the shelf I wanted/could stand paying money for, so I paid normal price for it.
I wonder if at some point I will regret not just buying 5 copies?

@KingMike: It was by that Classic Game Room review that I first heard of the game

Yep still picking up games for my Wii (which was my most ignored collection sadly)

Recent Pick Ups (Last Week)
-NiGHTs Journey Of Dreams
-No More Heroes (Both)
-Sonic Colors

Next On My List
-Skyward Sword
-DKC Returns
-Mario Galaxy 2

I recently picked up Fire Emblem: Radiant Dawn for $15 clearance price and must say that I was thoroughly pleased with my purchase and don't understand why the game is considered the black sheep of the Fire Emblem series.

Just picked up Kirby's Epic Yarn brand new from ebay for $12 with shipping. It's still a good time to own a Wii.

Got Family Ski & Snowboard in mail yesterday, but I haven't tried it yet since I wanted to finish Chicken Little: Ace in Action first. If the game had subtitles, I might've enjoyed it a lot more - now, I missed a lot of the dialogue spoken (and likely pop/scifi culture references) because of the cast, especially Adam West, mumbling something. And that kind of humor would've been a good extra point for the game, even though most probably not even nearly reaching the level of LEGO City Undercover. I'll be writing my subjective impressions post on CL:AiA tonight.

Any suggestions for third-party games? I haven't bought much but I want to before it's too late.

Arc Rise Fantasia, the most overlooked game on the system, IMO. Also, Little King's Story, Muramasa, Rayman Origins (I've said it a million times but still applies), and the Rune Factory games. All of those are pretty cheap too, I think. (Edit: Well, ARF is a little spendier...)

ARF and Rune Factory Oceans(?) never got to Europe, so if that's where you are, you can forget about those.

Looking back at what 3rd party games I've played and really liked (note that this explicitly states this is just a personal preference, your mileage may vary), I'd say Cursed Mountain, De Blob (1, I haven't played 2 at all yet), Dead Space Extraction (if you like on-rails shooters), Final Fantasy Fables: Chocobo's Dungeon (because Europe didn't get Shiren the Wanderer), Geometry Wars Galaxies (if you like twinstick shooters and have a classic controller handy), MySims Kingdom and Agents (I'm a fan of the franchise; SkyHeroes and Racing aren't anywhere as good), Opoona, Red Steel 2, Silent Hill: Shattered Memories, Sonic Colours, Trauma Center, We Cheer (if you are in NA, the sequel is preferable due to it being easier, I hear).

Yes, the catalog is now cheaper and it is a good time to get cheap great games. I bought the last week in a promotion of RadioShack Punch Out and Super Paper Mario both for $400 pesos (it is like$30 dollars) completly new.