A custom saddle makes all the difference in the ride for me. A good saddle in leather can run you about $300 - $700 US, but worth every penny.
Accessoires
I was looking for more visibility and possibly better night lighting.
A club member, Don Schmok, installed HID lights.
Another club member (Don) turned me on to LED headlamps last summer. The remarkable thing about them is that the three AAA batteries last something like 100-150 hours!