go on craigslist or ebay and pick up an LTD mh350nt, I had one for a while and it was great. Theyre about 5-600 bucks new, which puts them in your budget if you buy used.
x2 on schecters, I've had 2 schecter 7 strings and I love my current one, a c7 hellraier hybrid. it has the new 57/66 active EMG pickups which I really like, slim satin finish neck and ebony fretboard.
I'd stay away from the active pickups until you get more proficient, and by that point you may find you like the passives more. the LTD I mentioned before had the 81/85 EMG combo in, but I swapped the 85 to the bridge and it chunked up my sound a lot without sounding muddy. I was playing that thru a laney ironheart head in C standard and my god it was a brutal combo. I just dont get on with 6s anymore I have to play 7 string guitars because the neck is just so comfortable width wise for my hands.
Ibanez is solid I suppose but I've heard nothing but good about the Jackson JS series of guitars. I had a Jackson at one point too, a made in japan pro series dinky that I really liked. I hated the bolt on construction though it was the only caveat I had with it.
Go fixed bridge for sure, trems are useless on guitars in your budget. a basic tune o matic string thru body set up is ideal for metal playing.
overall id grab a used LTD 300 or 400 series guitar, make sure its made in indonesia not china. The neck will be comfy- slim but not overly thin, it will be finished nicely and feel rock solid. Good pickups too, usually EMG or seymour duncans depending on the model. I like the horizon shape the most, but the eclipse is a fantastic guitar too, and EC401 is a solid guitar for the money. if you can find a good deal on a korean made schecter thats also a great choice. I like the banshee series and the hellraiser series a lot. the banshees come with active or passive pickups,, your choice, and locking tuners and low profile hipshot bridges (GREAT BRIDGE take it from a guy who loved his tunomatics for years).
Dont buy from guitar center either. That place sells used guitars as new. Ive seen off the shelf fenders with scratches all over the pickguard cus some kid came in and played green day and metallica for 2 hours with a crappy pick. speaking of picks, try the jazz 3's. great pick for metal.