From working at a REI for some time, I feel I can speak a few words about boots.
Getting the right boots are all about the applications your going to use em for. I guess I'll just give some guidelines for choosing an all around good boot.
-Waterproof: if your looking for a boot that is going to be waterproof, i hate saying it but your going to need a pair that has a Gore-tex liner. Other boots that are labeled 'Waterproof' or something similar usually only have a coating that makes them temporarily waterproof, or have a similar cheaper way of 'waterproofing' them. Gore-tex is an actual membrane that sits in between the layers of fabric in the boot. They provide the highest waterproofness while still being breathable. Also, Gore-tex does provide some sort of warranty, so if they start to let water in you can usually send 'em for a repair/new pair. (to make sure, gore-tex boots will always have their label on the boot. if you dont see it, its probably not gore-tex)
-The Sole- Sole's are really important because its the area of the boot that will get the most wear (duh). I highly suggest getting a boot with a Vibram sole. Again, i hate touting brands and shit, but Vibram soles are GUARENTEED FOR LIFE. so once you wear it out, you can bring them to a vibram sponsored shoe cobler, or send them in and get them completely re-soled FOR FREE! this is great. i have seen 10+ year old boots with new soles and it makes the boot look brand new! any boot with vibram soles will have it stamped on the bottom.
-Insulation? if your looking for something on the warmer side, going with an all leather boot, especially with a gore-tex liner, will be the best option. i talked to a lot of serious hikers/backpackers that used all leather boots even in the winter. the leather + the gore-tex liner makes for a warm boot, esp with the right socks. if your not looking for something super warm, they make boots that are mostly leather with some mesh vent holes. as long as they have the gore-tex liner THEY WILL BE WATERPROOF - even the mesh.
-Stiffness: This is important! depending on what you carry, your going to want a boot with a STIFF SOLE. stiff soles provide better support. if your planning on carrying heavier gear, your going to want a stiff sole. in general, stay away from soles that you can bend easily. stiffer=better. word to the wise: stay away from boots with 'steal shanks' etc in the sole. these just make the boot heavier and are generally on cheaper boots! good boots these days dont use 'steal shanks' anymore. i think its some sort of carbon or hard plastic.
-Other stuff: if your planning on carrying heavier stuff or need more support for your knees?back, get a boot that sits higher up on your ankle. these will be more supportive. make sure the boots have a removable in-sole. make sure the boots have good laces-they will rip if they suck!
Good places to find boots: Places like REI and EMS and maybe other outdoor stores usually have an in house brand that sells for cheaper but are made by the big brands. these are usually good buys. Also, REI has these things called yardsales where they take all the used/returned/'damaged' gear and set up a sale in the back of the store and sell everything for REALLY CHEAP. i'm talking insanley cheap. all you have to do is be an REI member ($15 or so for a lifetime membership) and ask when the next yardsale will be. generally they are every few months.
If anyone has any other specific questions concerning boots or certain brands, ask away. I sold boots/hiking shoes for a solid year and talked to a lot of experienced people about these things.