One third party controller woth checking out would be the mad catz controllers. I have a wireless one, with is much easier to handel then the first party wireless. And two of my friends have wired madcatz controllers and they've all worked fine for years.

(Lucky for me I have four cube controllers already.)

Just check out GameStop for Wavebirds, I bought 4 (one at a time) for $14.99 each over a ten week period, people trading in Cubes frequently trade in original and Wavebird controllers.  If they didn't have one (which was most of the time to be honest), I just checked back again untill I loaded up! The key is checking frequently, as they usually go the day they get them. The demand is only get bigger, so start now.

Maybe they won't in order to increase Classic Controller sales

I can't wait to use Wii-mote and nunchuk in Brawl. GameCube will be my 2nd most used.

If they were smart they would,theres no way i could picture playing brawl using the wii-mote...

I bought 4 GC third party controllers a couple weeks ago.

As always, I'm disappointed...I got them SUPER CHEAP, and they're the kind that look EXACTLY like the 1st parties except no Nintendo logo.

But the joystick's kinda unresponsive...I've missed an Up jump a few times, and constantly do my B-left or right moves instead of B-up when trying to save myself....LAME.

But I only spent like $30 on the set from eBay. I figure I'll switch to the Wiimote+nunchuck setup...they're wireless and have Wii power and home buttons, which is useful of course.

And I figure instead of having C or Z for jumping, whichever one it is...I'll only use up on the nunchuck's joystick for jumping...that's what I'm used to. That way I can keep C for grabbing and Z for shielding...I like to use the button for grabbing....I'm stubborn.

I've never had any trouble getting hold of them, there are always plenty on eBay.

If you want new ones then Play Asia has them in stock: http://www.play-asia.com/SOap-23-83-74vc-71-23-49-en-84-j-70-1ps.html

Is it vital to own a GC controller or will the Wii mote work as well?

No it isn't.