Hi guys i ve just started out playing guitar and i am looking for a good solid state practice amp. I like to play a variety of styles but metal is my main genre. Ive narrowed down to peavey vypyr 30, roland cube 40gx, blackstar id core 40 and yamaha thrx( i am leaning towards the yamaha but few reviews on the internet says that the small speakers arent good enough to compete with the amps with bigger speakers) Please help me chose one.
Ps: ill be ordering the amp online.
Depends on how you plan to use the tool. See the amp sticky to narrow the field a bit.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
I am planning to use the amp mainly for practicing and recording stuff. I wont be doing gigs as for now.
The first thing that comes to mind is the Peavey Vypyr Tube 60. It uses power tubes with a SS pre section. I only know it by reputation though, have not tried it myself. I did try one of the completely SS older model versions, and was impressed.
The THR - from what I've heard - is a great little amp, but it is little and it won't be much good if you want to play with a drummer or even another guitar player. The other three amps you mentioned are all solid choices for what you need. Plug into them and see which one you like the best at the store.

If you can't play them, see if any of them have a feature that you really want that the others don't, if they're still all equal choose based on price, they are all fairly comparable. Lets be honest, this is your first amp, its not going to be your last, or best amp, its not supposed to be, its supposed to get you into the game, and give you enough tonal variety to play most types of music with a decent sound.
If you want modeling go the Vypyr route.

If you want a regular type of amp look for a Randall RG. You can get a lot of RG used for little $.
Ibanez RG1570 Prestige
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)
Fender MIM Strat

Mesa/Boogie Dual Rectifier Roadster 212
Laney IronHeart IRT-Studio
Peavey Vypyr 30
Peavey ReValver Amp Sims
TOOOO many T.C. Electronic Pedals. . .
Lots of great suggestions out there. I think peavey vypyr seems to be a better bet for metal, still i would try to play them all before buying.