Yup, once you have your short list, check the Hot Deals section here and some sites like Dealighted to find any good deals out there on it. If you're up to buying thru eBay, then a browse there may turn up a deal on occasion. And sometimes your local Craigslist listings may have something. Then there are always the price comparison sites like PriceGrabber, PriceWatch, etc. Always check Provantage and Amazon when shopping for Antec cases.
You have an over 2000 post count, so just by osmosis you ought to know by now which resellers are considered tops around here: Newegg, Directron, MWave, ZZF, SVC, Jab-tech, etc. All have exclusive deals and rebates from time to time, so it pays to check their sites out. As was said above, no one place always has the best deal on every model, so you do have to shop around if price is important to you.
I also usually have several cases in my FS/T thread which is linked in the sig of my posts. If you just want an excellent, inexpensive case, the Rosewill R5600 series has been at good special prices lately. Check my review here:
http://www.techimo.com/reviews under Cases and all the way at the bottom of the list. I currently like the 5605 version over the others. The Rosewill R6A series which I mention in the review is also almost always a good buy. But if you have (or expect to get) one of those 10.5" long vid cards, then the 5600 series is the one.
.bh.