I'm looking for a cheap amp to practice with in my room, but I'll be playing it almost exclusively with headphones. I need something probably no bigger than 25w, and between $100 and $200. I want it capable of good metal tones (Megadeth tight or Mastodon chunky if possible in the same amp) I know it's not going to be the best of tones for my price range, but I can work with a pedal if I need to. I just want something that isn't too muddy, beyond distinguishable.
I used to use a Line6 Spider III before I bought an Orange. The tones aren't fantastic, but if you get a cheap effects processor like a Digitech RP50, you can get some decent sound out of it for the money.
If your going to be using it mostly with headphones, then maybe you would want to look at a multi-effects unit. Many of the Line 6 Pod units are pretty decent, along with the Zoom G7/G9.
If headphones playing is your thing, Line 6 POD without a doubt.
Telecasters-->Dunlop Volume Pedal-T1M Pearl-AMT Japanese Girl Wah-Line 6 M9-Ibanez DE7-EHX Cathedral-->Mesa Boogie Nomad 4x10 combo
Ditto on the line 6 stuff. Lots of people hate on Line 6, but if you know what you're doing on the composition, performance and mixing end you can make almost any amp sound great.

If you're going the headphones route a line 6 pod or even vst amp sims is probably the way to go. I'd take the pod over the amp sims though.
With headphones, a mfx unit like the zoom g3 or the digitech rp355 would be a good choice. Both sound very nice through headphones.
Guitars: Fender FSR Standard Strat, Squire Affinity Strat, Epiphone Nighthawk
Amps: Vox AC15C1, Roland Cube 15x, Peavey KB-1
Pedals: Digitech RP355, HD500, Joyo AC-Tone, EHX Soul Food
My biggest concern is getting a "tinny" or flat sound out of it. I'm going to be using some decent headphones (should I get special "stereo" headphones?) and I want to feel the warmth and the "chug".
if you want a budget metal practice amp a peavey vypyr is perfect, i have one and its far better then any of the line 6 amps ive tried (i owned a flextone II and desposed the spiders distortion when i tried it)
Proud owner of Paul Allander PRS styled - Shamray CS-1985
CS-1985 Pics
Jackson RR24 White with black bevels
If you want a amp I would agree with the Vypyr recommend. If you want headphones I'd go for the multifx. IMO the headphone out on the Vypyr isn't great, but others may have a different opinion. Multifx will give you stereo.
Your not really going to get a good warm tone, and good chug on a budget like that.
I just want something I can practice with in my bedroom with headphones. If I have to use an FX board for versatility then so be it, but I want a bit of "feeling" in the sound, and a decent metal/hard rock tone.
why not use a computer interface and a vst plugin on your pc to practice in the bedroom
Vox VT15, or maybe a mustang or something
G(g)od was like: "Make you an ark of gopher wood; rooms shall you make in the ark, and shall pitch it within and without with pitch."

And i was like: "What's gopher wood?"