Smudge is right. There are lots of opinions. And we all know what opinions are like.
So lets start a little differently.

Ask yourself what kind of items do you want to find? These can be things like coins, old coins, jewelry, historical items (relics), caches of coins and valuables, and metal nuggets (prospecting).
Then ask yourself where you plan to do most of your hunting. Are you going to stay primarily in a town (urban hunting), in your county (urban and field hunting), on beaches or in water (fresh or salt? - it makes a difference) or do you plan to travel all over the country or the world?
Now, does what you want to find conflict with where you want to hunt? For example, urban hunting and prospecting don't go together well. Neither does beach hunting in the desert.
Next, think about how much you want to spend on a detector. That's the detector. You can easily spend hundreds in additionals such as head phones ($30-150), digging knife (trowel) ($30-40[don't go cheap] , pin pointer (don't go cheap there, either. Garrett is probably the best hand held [$120-140]), carry case, etc.
Once you've narrowed things down a bit, talk to your local dealers. Don't like the local guys for whatever reason? Then check with the forum sponsors or pm me for the name of the shop I use.
Hope this helps you a little. And. no, I didn't get into the brands spitting match. We all have personal preferences, and you get to develop yours all on your own. But at least you know how to start.
All the best with your new hobby and Happy Hunting.
Dave