My 9-year old bike with 8-speed Shimano Ultegra STI shifters has been giving me shifting troubles that tell me the chain / cogs are worn (again) and the rear derailleur is probably worn out. The mail order places don't carry any 8-speed stuff anymore and my LBS doesn't have much. So it looks like planned obsolescence has won and I may have to upgrade just to get parts. Can anyone comment on the availability of 8-speed components? Do you know a source of parts?
IF I decide to upgrade, should I go to 9-speed or jump to 10-speed? If I recall, the dropout spacing is 130-mm for all three.