I'd echo what others have said - there's many good choices, but personal preference is very subjective so it's best to try to handle the knife before you buy. Here are some links for browsing purposes, and I have focused on decent-steel knives around or under your range (I just picked knifeworks & knifecenter for convenience, there are many good internet vendors):
BM ambush - I have seen but not handlked these new knives, they are big and sturdy and inexpensive and have gotten good reviews here. Strong lock, AUS8 blade
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=4365
BM AFCK - AXIS lock, dual steel liners, D2 blade, great ergonomics
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1634
The TSEK is very similar, but with 440C steel and about $40 cheaper
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=2464
BM 710 - AXIS lock, dual steel liners, recurve ATS-34 blade (for $15 more you can get the M2 steel blade, which gets raves for sharpness and edge-holding)
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=202
BM Griptillian - AXIS lock, dual partial liners, 440C blade (Cabella's has them with D2 blades), great ergonomics
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1546
Buck Strider - bulkier than most of the other choices, but with bulk comes strength
http://store.knifecenter.com/pgi-ProductSpec?BU880SP
Spyderco Endura - tried & true, great VG-10 steel, lightweight handle or for a few dollars and ounces more a stainless handle is very solid
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1436
Spydie military - single liner & G10 scales, liner-lock, S30V blade is a great cutter
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1753
Spydie Native - these come lightwieght, with or without 3D contoured handle, or stainless handle, VG-10 steel, stout knives
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=3710
Spydie Police - doesn't get talked about as much as some of the others, but it's a tried-&-true workhorse
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1749
Spydie Persian - a new knife, looks sweet, it's getting great reviews
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=4480
Spydie Chinook II - what can you say, it's a fearsome tank, 440V blade
http://store.knifecenter.com/pgi-ProductSpec?SP63GP
Cold Steel Voyager - these come in various sizes, not as upscale as some of the others but you'll never hesitate to beat the cr@p out of it. Zytle handles, AUS8 steel, lockback.
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=439
CRKT makes a lot of knives, some better than others, but the M18 has gotten good reviews & would suit your needs. It has a liner-lock plus a secondary LAWKS lock to keep it locked no matter what, and a "flipper" that allows for fast opening, plus a recurved AUS8 blade
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1564
A few people really like the Timberline Wortac:
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=3545
This Lone wolf is over-budget but pretty darn sweet - me, I'd be reluctant to bang it up, although it could take it
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=4362
Kershaw has a bunch of "assited opening" knives designed by knife genius Ken Onion. Most aren't great steel but a few in your range are good:
Avalanche - my favorite, oustanding design, blades used to be 440V but now I think are S60V?
http://store.knifecenter.com/pgi-ProductSpec?KS1570BK
Boa - CPM-440V blade w/a deep recurve & flipper
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=339
Seagal (not speed-assisted)
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=3714
Al Mar SERE - a bit bulkier and pricier, but very popular
http://store.knifecenter.com/pgi-ProductSpec?AMS2K
& their Shrike is a little sleeker, but also pricy
http://store.knifecenter.com/pgi-ProductSpec?AMSKE2
SOG doesn't have as many followers here, but the Pentagon elite is worth looking at
http://store.knifecenter.com/pgi-ProductSpec?SOG14PEA
And, let's not forget that excess can be just what's called for, i.e. the CUDA MAXX - 5.5" of D2 bowie blade in a slim titanium frame-lock; "go big or go home!"
http://www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1708
Well, that should keep you busy, eh?