I decided to post regarding the recent poll regarding Dynasty mode, noting that most people only play a couple of years.
Is this because the game gets less interesting once the current NBA guys retire or age and the league becomes dominated by generated rookies? I actually prefer to play the game for the full length of the dynasty.
Usually what I do is take the current rosters, but do a simulated draft so that the rosters are mixed -- I'm not big on trying to recreate exactly what one might find in the current NBA season / playoffs, it's much more interesting to mix things up.
As the computer generated rookies start to dominate the dynasty in the later years, I edit a good portion of them (both ratings and appearances) to populate the league with some more interesting players (as most generated rookies are crappy/undersized/etc). A lot of the players I create are based on past great players.
Sometimes I like to create players with really unusual and conflicting characteristics -- like a 5'5 high-flyer, that can run the floor with incredible/speed quickness, and play some damn good defense, or a big center that moves incredibly well with the ball, with great dribbling skills and a three-point shot and unleash them on the league.
Another trick I like to use is to take a crappy player on the FA list and up his stats, so that the next year, a team that needs a great player can sign him for peanuts. This often helps counteract things when one or two teams really start dominating a dynasty.