An alternative to the Lycra is a baggy Mountain bike short, but I prefer the lycra due to the muscle compression it provides. It aids in circulation on longer rides and is also less aerodynamic drag.

Another aspect of Lycra is abrasion resistance, it tears less easily if you go down on the road and reduces the risk of road rash!

the best Clyde and Uberclyde source I've found for cycling shorts, tights, and other clothing gear is http://www.aerotechdesigns.com