If you're not going to do any racing (crits or road races), then you can select 12-25 or 12-30 Ultegra 10-speed cassettes. Only drawback is that they are $65 and $75 respectively. The 105 11-25 one is $38 at universal cycles. Its not great that 105 only has one option, but it is what it is. Maybe there are some other sources for 105 10-speed cassettes.