1. Daft Punk
2. Muse

After these, there is a large number of musicians, and I can't establish any order.

Honorable Mentions: Django Reinhardt and Stephane Grappelli,

Ooh, that's a tough one! I guess it would have to be something like this:
1. Amorphis
2. Poets of the Fall
3. The Sounds
4. Machinae Supremacy
5. Nine Inch Nails
Of course there's changes happening constantly and I haven't really thought about the order that much either.

no particular Order subject to change
Joe Bonamassa
Black Country Communion
Led Zeppelin
Frank Zappa & Mothers
Rory Gallagher

5) Green Day
4) GOB
3) Blink 182
2) Billy Talent
1) Sum 41

1. Dylon
2. Dylon
3. Dylon
4. Dylon
5. Dylon

He spit hot fire!

1. Joe Strummer (The Clash)
2. Johnny Cash
3. Chester Bennington (Linkin Park)
4. Geddy Lee (Rush)
5. Gordon Downie (Tragically Hip)

1. Massive Attack
2. Girls
3. The Strokes
4. The XX
5. Gas

Seriously though, I would say something more along the lines of:

1. Mariah Carey
2. The Beatles
3. Tupac Shakur
4. Celine Dion
5. The Doors

Really in no way indicative of the music I listen to, these are just 5 out of my favourite 40-50 bands/singers. There are many more I feel deserving to be included in my "top 5". For example, I probably listen to Chic, Depeche Mode, and Duran Duran as much as I listen to these other bands.

There are many acts I like several tracks from so my top 5 will have to be based on their whole career and continued quality of works:

The Beatles

Pet Shop Boys

The Prodigy

Muse

The Smiths

other favourites include Breaking Benjamin/Red Hot Chili Peppers/Radiohead/Foo Fighters/Eels/Morrissey

and if my son's band continues with the quality of recordings I've heard so far they are also going to be making the list at some point:

Salvation, Salvation by Big Sixes