Originally Posted by
Alyx
if I raise the seat I wont be able to reach the floor.
Depending on bottom bracket height you should barely be able to get a toe down with your butt in the saddle while it's at a proper height.
See here for a video on what is generally considered appropriate mounting and dismounting technique:
http://sheldonbrown.com/starting.html
If you're just riding around a low seat doesn't matter, but if you ever get into longer distances it can start causing knee problems as the quadriceps will overdevelop and patellar tracking gets knocked out of whack.