Who are the "Must Have" prog rock bands for someone who's just getting into prog rock?

Tool is the worst band ever, you wouldn't be able to capture the beauty in any good band so i'm not even going to list any except maybe Barney

Porcupine Tree

Opeth (The best Prog band in my opinion but they aren't purely prog rock)

Dream Theater (brilliant band with incredible instrumentals)

Rush

Pink Floyd (These guys are a must)

King Crimson

Edge Of Sanity (Along with Opeth they are an early pioneer of extreme metal and progressive mixed)

Mastodon (Have a unique blend of Sludge Metal and Prog)

Yes

Lake & Palmer

Deep Purple

Storm Corrosion (This band isn't Prog rock but extremely influenced by it, it's very dark and ambient)

Opeth:

http://www.youtube.com/watch?v=v0wBNbZjlfw (Shows both sides of their music)

http://www.youtube.com/watch?v=u3W-WYO8k4M

Pink Floyd, Dream theater, King crimson, Yes, Rush, Genesis, Emmerson Lake and Palmer, Jethro Tull.

BQ: Currently listening to Symphony X which is an underrated prog metal band.

BQ2: maybe..

Rush

King Crimson

Some Thin Lizzy stuff is pretty progressive

Emerson, Lake and Palmer

Deep Purple

Rainbow

Jethro Tull

Led Zeppelin

Mastodon is new but they're cool too especially Crack The Skye (album)

BQ Search and Destroy by The Stooges

BQ not at the moment I'm busy watching porn

Dream Theater

Cynic

Meshuggah

Yes

King Crimson

Opeth

BQ: Dillinger Escape Plan!

Dream Theater

BQ: Tool, Incubus, Good Charlotte

BQ: I'll try to