I also like MarineDepot.com and ThatFishPlace.com for a variety of skimmers. But some of the best quality ones can be ones that are made by a single vendor and not sold in stores like myreefcreations.com.
You really have an OVERLOADED amount of choices. Figure out what size sump you can accomodate first, then see what will fit in it. On your size tank I'd avoid the hang-ons unless you have some serious back wall clearance for a good one and won't mind the occasional micro bubble. I don't like ANY bubbles in my tank so I stick with in-sump ones.
BTW...There are also some sump skimmers than can sit NEXT to the sump and not IN it. It all depends on your space so like I said...see what sump you can fit first, then see what clearance you have for a skimmer since that can be a serious hinderance to those that don't have "fish rooms" with open sump setups.