I wear cowboy boots almost every day and have since I was about 12 (now 27)! Some good ones to try:
Lucchese - always fit me exceptionally! little to no break in time, you will need to be fitted for size though. IF your foot is more on the narrow side you should be happy with the way these fit. The 1883 collection is fabulous! My last 5 pairs (in 5 months) have been from that design line. Zappos has really good styles right now!
Old Gringo - much like Lucchese, but a little "louder" styled so to speak.
Anderson Bean - totally handmade, sizing is iffy though. You'll have to go to their website, (I always google it) to find a retailer as they are B&M only usually. They have some fabulous exotics (ostrich, gator, etc) and you can custom order. They're really big on the square toe which is very in in alot of horse/rodeo/cowboy circles. Personally, I'm over it-it's been about 5-6 yrs of the trend.
Justin - if you want a classic more true cowboy boot, they have some good styles that will last forever.
Frye has good boots that are less "cowboy on the range" that look and wear great as well.
That said, I would not be caught dead in the following: Laredo, Dan Post, etc. They're cheap for a reason! I don't do cheap!
Also, decide on the toe style (pointed, but not too pointed aka roach killers

- personal fave, square, round - not the best looking, but comfy) you want and the sole (leather or crepe usually). You can find a great looking go with everything boot for around $200-$500. I would start around the $200 end and go from there. Keep in mind, exotic leathers, stitching and handmade or customs cost more. I wouldn't spend a whole lot until you see if you like them and would wear them enough to offset the cost. They look great with most of my wardrobe, but that varies greatly form person to person. Hope this helps!