I used to love dark heavy beers, and still have a nostalgic loyalty to Spaten Optimator, which is hard to find but is the most smooth, sweet, deep dark beer I have tried. But most of the time now, I like something lighter and really have gravitated to lagers. They are easy drinking year round. And I have found you don't need to get fancy or expensive with lagers -- some of the best ones are mass production brews.
For a summer beer or refreshing beer, Land Shark lager is inexpensive but quite good. Similar to a Corona, but more flavor and lager depth (I find Corona to be a little watery).
Something in the middle would be Michelob Amber Bock. This is darker but still easy to drink.
Sam Adams is a favorite too.
Anything labeled as a "Vienna lager" from any brewery is usually worth a try for me. Some are great, others just decent.
I'll pretty much enjoy any beer, but can't stand most IPAs. Too peppery/grapefruity/floral for my taste and do not pair well with any foods. I was talking about this with a friend who is a beer expert/judge, and he says it's due to the type of hops most modern brewers are using, which give those floral tastes. Apparently with the proper hops, and IPA is a completely different animal. He has tasted an IPA made with the right hops, and says it was a completely different beer.