Excal 1000, Excal II, Sovereign GT, CZ-20, Tiger Shark, Tejon, GTI 1500, Surfmaster Pulse, CZ6a, DFX, AT PRO, Fisher 1235, Surf PI Pro, 1280-X, many more because I enjoy learning them. New Garrett Ca
Research depends on what you are looking for and the area, what equipment you have. Some like to look for caches so their research is different from the guy or gal wanting old coins or relics. The beach hunter wants the oldest used beaches with the chance of finding Spanish treasure as opposed to fresh drops. I don't do any research at all anymore and just head out for the nearsest swim area to save on gas.
My research starts, with eye-balling the local web-cams, at my beaches. Seeing how many peoples, where they laid out at, what they doing(throwing balls are great way to lose rings), if they look like they are frantically looking for something. But, it's hard to tell if they're tourist looking for seashells or a lost ring! LOL!
I use a lot of old plat maps, and a state tax website to see the age of the structure, if it is still standing. If it is not standing, I use the old maps, and then locate where it was with Google earth. A lot of work pays off. You are more likely to find older things at an 1850's house, than a 1950's. Try this out my friend! http://www.historicmapworks.com/Browse/North_America/
Go to your state, and then county. Best of luck!
I don't need much research to START looking (notice I said START). But in the course of following the lead, I will do a ton of research. In fact, I will probably do a lot more research then actual searching. Of course, I'm talking about cache hunting.
I see things on the news or read in the local paper, a demo job or some park issue...and I'll do a quick search on the location to see if holds some early history or how old the park is...kind of neighborhood, etc.
If I want to do some relic hunting, then I go a bit more in-depth with comparing maps, reading old books, land outlay and property owners.
A couple treasure legends I spent many, many hours...days on end in libraries and historic societies researching and trial runs to areas scoping out the lay of the land, etc.
You can do as little or as much research as you want. I'd say the more research you do, the more apt you are to have better finds. The obvious places have been hit pretty hard around here so you have to be a little more diligent in your search of sites.