Aight, I'm really not liking my Line 6 Spider II 30, and so I'm on the quest for a new amp again. I play stuff like bullet for my valentine, Metallica, Killswitch Engage, Pantera, and all of that other good stuff. However, I want the flexibility to play stuff like Rise Against and other punk rock bands.

My budget is $200-$300
Fender 1989 MIJ Strat (It's from the 80's, so it's gotta be legit!)
Breedlove AC25 SM
There's nothing you can get for that to improve over the amp you already have. I'm pretty sure thats the price range of the Line 6 (the amp you already have). Usually when upgrading, you will have to spend more money than previously, not the same. Save your money and buy a decent tube amp later on ($500+). If you want a quick fix, spend like $100 on a distortion pedal.
Save your money and/or sell your Line 6. Also check eBay. If you dont want to do all that, just get a distortion pedal like South said.
Hail Satan

Yamaha RGX220
Peavey 5150
Trohak Cabinet (w/ Eminence speakers)
Mesa/Boogie 2x12 Roadster
Marshall Mg15
Get a Marshall AVT 20, the gain is like any other Marshall which metallica used along with a mesa. This amp has got a tube preamp, which is very nice for gain. The price is 299.99 USD. I have this amp and i really like the way it sounds and its actually pretty loud for 20 watts and it helps to put it on top of something and it will go over drums with a heavy hitter, barely over half up. Im sure it will beat the Line 6 amp u have. My 2 cents.
Check Out:Stack Of Noises
My SoundClick

Mesa/Boogie Single Rectifier Rectoverb
American Fender Limited Edition
Epiphone Les Paul Custom
Jackson Professional Rhoads EX EMGs
Pod XT Live
Marshall AVT20
1984 Peavey Pacer
Boss NS-2
Cube 30/60 would probably be your best bet. But like SouthWillRise said, maybe you should just save up a little more and get something that will last you awhile, instead of just going for a quick fix.
If you could blow up the world with a flick of a switch,
Would you do it?

If you could make everybody poor just so you could be rich,
Would you do it?

With all your power,
What would you do?
If you NEED a amp right now get the Cube 60
My Gear:

Ibanez Prestige 1570L
LH Fender Standard Stratocaster Arctic White
Ibanez Gax 70L
Roland Cube 30X
Vox V847 Wah
Boss BD-2 Blues Driver Pedal

RedSox are better than you.
Sell your line 6, save up a bit more, and then look at a used tube combo. ($500-600 ish?)
Rainsong BI-WS1000N2
CA Blade Electric
PRS Santana SE
Ibanez Artcore AF75
Carlo Robelli Jumbo A/E

Fulltone Fulldrive2
EHX Small Clone
Buddha Wah
Ibanez AD9 Delay
Ibanez Vintage EQ

Crate V18-112
Peavey Vypyr 75
Roland MicroCube
I can extend my budget to $500, so are there any more amps you could recommend to me (sorry that i'm doing an already done to death thread)
Fender 1989 MIJ Strat (It's from the 80's, so it's gotta be legit!)
Breedlove AC25 SM