Yeah, always juniper, though the minimum for line rate GIG is going to be an SSG550 I think...not for 2k though...
You're best bet is likely a SSG320 which I think you'll be able to find in your budget.
In terms of other brands the Cisco ASA is trading on the Cisco name alone, it's not a fantastic bit of kit (not terrible either though). Sonicwall and Watchguard I wouldn't touch with a bargepole. Fortigate is interesting, well priced, very high performance but personally I despise the interface and I don't think it has the enterprise pedigree (with is also my main complaint about the Sonicwall and Watchguard).
You do not need that kind of performance though, my current employer host in the region of 15,000 web facing servers and on the average day outgoing bandwidth is ~6GB/s. I can name only a couple of dozen customers who regularly use more than 100Mbps (and we're talking massively well known websites with load balanced server farms for those)