It really depends on the company you work for and the type of flying you do. There are a lot of disaffected pilots in this industry as it continues to evolve in an ultra-competitive, low-cost, post-September 11 environment. Conversely, a lot of guys (and girls) really love what they do and couldn't imagine doing anything else.
My career has had a myriad of incarnations and each has been different, fun, challenging and kept me motivated. My current company (who I'm very happy with) has me flying long-haul in a B744, works me about 17 or fewer days per month, operates to lots of interesting locations and pays me a lot of money. The downside is being away from home a lot and occasionally having a very mucked up body clock.
Think long and hard and talk to as many people as you can before you spend your dosh on flight training. Also, ask yourself whether you honestly have a passion for flying. If you dont, I wouldnt recommend this career path. Good luck!