Mine, in no order:

Story of the Year
Biffy Clyro
Gaslight Anthem
A Day to Remember
She & Him

Yours?

As we all know, these can literally change from day to day.

Currently:

Ulver
Wolves in the Throne Room
Agalloch
The Flight of Sleipnir
Danzig

Fractal Spasm
Boron For You
Commissary Disarray
Settle
Crud Poles

We understand if you're afraid to post because your list starts with Nickelback or Kid Rock.

Emilie Autumn
Inkubus Sukkubus
the Misfits [yes I actually like the current incarnation]
GWAR
Freezepop

No fear here, Nickelback is on my list but hell no to Kid Rap/Rock

Alter Bridge
Megadeth
Iron Maiden
Ratt
Nickelback

Miranda Lambert
Overkill
Weezer
Jewel
Danzig

Radiohead
Pearl Jam
Sloan
Weezer
Nine Inch Nails

They Might Be Giants
His Name Is Alive
Sonic Youth
The Magnetic Fields
Asobi Seksu

If we're including individual artist in with the bands, any of these lovely ladies could be swapped somewhere into the above list depending on the day:
Kristin Hersh
Joanna Newsom
Amy Rigby
Lucinda Williams
Lisa Germano

(and also a special mention to the band The Sparks, who I'm just discovering but seem to be pretty awesome in their 40 years of existence)

Foo Fighters
Radiohead
Pearl Jam
Queens of the Stone Age
Arcade Fire
Rolling Stones - if your still counting them as currently active.

Can't believe i forgot them

Off the top of my head:

Frankenstein 3000
The Queers
Dillinger Four
Motorhead
Jim Jones Revue

edited out Slayer and put in Motorhead.

Sticking to the thread title, I am omitting any solo artists from my list and sticking to bands and groups only:

Sonic Youth
REM
The Cure
U2
Queensryche

Propagandhi
Capital
Such Gold
Polar Bear Club
Strung Out

Currently active I assume meaning still making good music, not currently active meaning used to be good, technically still around but now turning out crap. Also, everyone already picked Sonic Youth, so I'll go with:

Mastodon- I'll buy anything they release for now.

Phoenix- Who have made a bunch of great records so far but seem like they're just now hitting their stride and will release yet another bunch of good stuff shortly.

The National - maybe not the most flashy band, but their music sticks with you

Fucked Up- who are continually pushing themselves and producing great music. They released a 13 minute hardcore/shoegaze/Brian Eno/motorik/Chinese masterpiece this year. Any band that can pull that off is worth liking.

Gorillaz - I can't see Albarn ever releasing anything shitty.

Nails are still active? i thought reznor was taking some substantial time off?

Yeah your right on that. I will sub them out for Sonic Youth who will be active well past the end of the Earth.

Iron Maiden
The Flaming Lips
Tool

Uh, that's all I got.

Drive-By Truckers
Twilight Singers
Jason Isbell
Ryan Bingham
Neko Case

Devo
Killing Joke
OMD
Spoon
The National

Phish - they've been close to top form since coming back last year
Umphrey's McGee - for 2 years i've hought that they were peaking, they keep getting better
Ween - been painting the town brown for 20 years, it still rocks
Bruce Springsteen - The Boss has entered a new era of his songwriting career, he's creating songs about hope and where America is going.
U2 - they're the biggest band in the world for a reason

Springsteen
Radiohead
Strokes
Dave Matthews Band
Muse

I don't know but there's not a whole lot, maybe the blue van, woggles, muck and the mires...running a blank already

Pearl Jam
Gossip
Yeah Yeah Yeahs
Radiohead
Arcade Fire

Pearl Jam
Idlewild
Coheed and Cambria
R.E.M.
They Might Be Giants