Welcome to the site! You have a ton of options and with a general question like that you are going to get a ton of different responses each saying to buy this one or that one. Think you need to first decide if you want single pin or multiple. Based on that then depending on your budget you can narrow down your choices. I have a Trophy Ridge React on my bow currently and really like it. I am going to be switching to a HHA single pin soon. I think both are great but that just my opinion. Good luck with your search. let us know what you decide on!
http://pages.ebay.com/link/?nav=item.view&id=221371918857 here is a good used sight that will go at a pretty good price
I have a HHA single pin. I really like it. I have the larger sight housing. I like the bigger sight window. But like jfergus7 said, there are many good sights out there.
As mostly everyone has previously stated, there are many good sights out there. I have an HHA single pin and absolutely love it. I have competed and won numerous state wide tournaments as well as killed my biggest deer to date with it. However, hunting with a single pin is where it becomes tricky. You must range your target, dial your yardage, draw and shoot. If the animal you are pursuing is walking, he just tacked on 5-10 yards, where as with a multi-pin sight, you can estimate and compensate without guessing where to hold. I have often contemplated going back to a sight with 3-5 pins but I can't get away from my HHA. Good luck and be sure to let us know with what you decide.