The Weber Smoky Mountain, or WSM, is a vertical bullet smoker that's $249 and worth every penny.
I have two of them which I use in competition BBQ. It's a short learning curve to use them, they go for 9 -10 hours without having to refuel (depending on weather conditions), are portable, cook lots of meat, and are one of the most popular smokers among backyard and competition BBQ'ers.
Yes, there is an entire website called The Virtual Weber Bullet http://www.virtualweberbullet.com/
which is extremely well done and very informative.
I would never get a low-end horizontal offset smoker. Too difficult to maintain even temps and you have to tend it much more closely. 'Course, lots of guys like that, since it gives them an excuse to not to anything else besides "watch the smoker", but I'm too busy for that.e
The Big Green Egg is a good choice if you have the money, want versatility (it's a grill, an oven, a smoker) and don't care about cooking a lot of food at once. They are very heavy, very breakable, and the flashbacks when grilling at high temps scare the heck out of me.