[collapse="Here's the Mega Man songs I have in my Project M..."]
Battlefield:
Battlefield (Main Theme Remix) = Dr. Wily Castle 1 Rock (Mega Man 2; 15th Anniversary CD Rock version)
Final Destination:
Final Destination (Main Theme Remix) = X vs. Zero Metal Remix (by AKHT & Akihito) (Mega Man X5)
Frigate Orpheon:
Vs. Parasite Queen = Metal Man stage (Mega Man 2)
Port Town Aero Dive (which reminds me, someone should make a version of this stage where it's just the platform and no interferences):
Fire Field = Snake Man Stage (original) (Mega Man 3)
Car Select = Nitro Rider ~Theme of Nitro Man~ (Mega Man 10 Image Soundtrack)
Dream Chaser = Quick Man Stage Remix (Mega Man 2)
Brain Cleaner = Dr. Wily Stage 1 (Abandoned Memory) Rock (Mega Man 10 Image Soundtrack)
Golden Forrest (1080° Snowboarding) = Against the Pressure (Mega Man 10 Image Soundtrack)
SSE Jungle (Formerly Distant Planet):
Ai no Uta (French Version) = Ruined Street: Mega Man 7 Opening Stage
The Summit (a Balanced version I downloaded from the Brawl Vault; look it up; it's freaking AMAZING!!!):
Shin Onigashima = Cloud Man (Mega Man 7)
PictoChat (now with less random crap!):
Opening Theme (Wii Sports) = Guts Man (Mega Man)
Charge! (Wii Play) = Mega Man 2 Main Theme (Metal Version)
Smashville:
The Roost = Cut Man [Mega Man 1] (Street Fighter X Tekken Mega Man Rival Battle)
Menu Themes:
Menu 2 = Mega Man Battle Network 3 Opening Theme (I'm going to try to find a non-looping version of this, and make it ROB's victory music)[/collapse]That's 14 songs I got in my Project M mod, and I still am thinking about adding at least 3 or 4 more!
I think any or all of those songs would be incredible to have in a Smash Bros. game!
When it comes to Wily Themes, I also think Mr. X stage from Mega Man 6 and Wily Stage 1 from Mega Man 7 deserve more mentions. They're some of my favorites.
That and a few of the Mega Man 10 themes.