I use realtyjuggler.com. It's very user friendly and it's CHEAP! Only $99 a year. AND it's web-based, which I like. You can track pretty much everything, make contacts, set appointments, track expenses, set follow-up dates, manage closings, etc etc, the list goes on. It's a great product in my opinion, and I know a lot of other local agents here use the same thing. You can try them out for free for 90 days at http://www.realtyjuggler.com.
Good luck! Josh Perkins, Your Castle Real Estate, Denver, CO, Local Knowledge - Total Commitment, 720.985.6834