What you need is one that has MPH, Total distance, total time. etc. I like the Cateye brand myself. Try to find one with Cadence. You'll probably want that feature sooner or later.
As for calories, no bike computer will have any accuracy.
Try the program at
http://www.cyclistats.com/
It takes a lot into consideration like aero position on bike, ave wind speed that day, type of tires etc. They have a free trial version (limited time) It is not shareware. I've been using it for 3 years. You can use it to track every ride, your weight, bike repairs and more. I found it very useful.