For a lower budget dot, i really like the Burris Fastfire 2, you can find em for under 200 bucks all over the place. The Fastfire 3 is about 40 bucks more and supposed to be a bit better so you may look at that. I currently have 2 Fastfire's and really like them. Ive had them mounted on everything from a .22 to a 12 gauge and never had any issues.
If i were to spend any more money i think i would go for the C-More, either the STS or CTS. They are all over the gun game sports and i imagine they are there for a reason. I think you can find the, in the 300 dollar range.
If you have more than that to spend, i would look at the Trijicon RMR or the Vortex Razor. I have played around with the RMR a bit, and didnt really care for it, but a ton of ppl swear by them so it must be good. I have not seen the Razor in person, but all reports are great and i REALLY like all the Vortex products i have got my hands on..
As for mounts, i like the slide top mounts so look at any of the dovetail mounts. But really, if you are going to go all out on one of the more expensive dots i would have my slide milled down for that mount.
