I carry a buck strider mini- tanto-serrated and I am looking for a bigger blade.
I love the buck/striders blade thickness, but was looking for something different.
My choices are

Buck/Strider 4"
Camilmus Maxx 5.5
Al Mar Sere Operator

I had a CRKT M16, but I am pretty rough on my knives and it didnt stand up too well.

Any suggestions?  Thanks

The Al Mar Operator that you mentioned is a fixed blade. The Al Mar S.E.R.E. 2000 is a folder, but it is under 4 inches. That should'nt stop you though as it has quite enough blade to do pretty much anything a folder should be doing. It is one of the nicest folders out there, bar none. Great steel (VG10), near custom level of fit and finish, bullet proof, tank-like construction and awesome ergonomics. Here are a few pics of mine,





Here is a great place to buy it, www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=1429


Another great folder is the Benchmade model 710. Although the blade is 3.9", it is a pretty large folder. I recently ordered one in the M2 steel and it is an awesome folder. Super smooth and solid as a rock with a very strong locking system (axis). Can't go wrong with this one. Heres some pics of mine,






Heres a link with the best price I have found, www.newgraham.com/benchmad30.htm

For a really large folder under $200, check out the Lone Wolf Harsey tactical. That thing is huge. I don't own one, but I have heard good things about them and have handled them. They use a great steel (CPM-S30V) and have great ergonomics. You might want to handle one first as they are very large and probably a handful to carry. I like big folders, as I carry an Extrema Ratio M.P.C. quite often, but some people prefer something a little lighter. I would recommend the Extrema Ratio, but it is a little out of the specified price range ($300).

Here is a link to the Lone Wolf, www.knifeworks.com/index.asp?PageAction=VIEWPROD&ProdID=5584

Good luck.

Check out the Benchmade Rukus. I think the model # is 610. I handled one at the shop the other day and its BIG. Basically a folding sword.

Try the Cold Steel Recon series.

I have several of the Buck/Strider 880 series and cant think of a better big super tough folder made with top of the line materiels.  If you look you can often find the full size models for under $100.

Spyderco Police or Military. Most bang for the buck.

I can't say enough good things about my Benchmade AFCK. Unfortunately, according to Benchmade's website they were discontinued in November. If you can find one in stock somewhere or a good used deal, I would highly recommend it.

Camillus Dominator. I carry it daily. Quick assist open, great blade, deceny weight. Next would be Spyderco.