One of these days I may buy a new bike, and I'm wondering if I should go with a new bike with a 10 speed cassette or a used bike with a 9 speed. It would seem to me that a 9 speed would be easier to maintain as far as derailleur adjustment and shifting ease. Is my thinking correct?

Also, where is cycling going next, is Shimano working on an 11 speed? How many rings can they fit back there? I was happy with my 7 and 8 speed bikes.

9 speed will not be supported much longer, so I wouldn't think it wise to invest in it. There will be some small loss in cog and chain life with 10 speed, but that's not a big issue when you consider that most shops and mechanics really don't know how to measure chain wear or optimize cog life. A lot of shops will try to talk you into a new cassette with every chain or two, rather than test the cassette for chain skip.

As far as shifting precision, there is no difference. The fit between the cogs and chain is that same as it's been for along time. The cog spacing is narrower, but so are the chains. Campy has even increased the clearance with the introduction of it's new, narrower chain (with the same cog spacing).

As for the future, it's possible to put 11 cogs with Shimano's width and spacing on the length of a Campy or Mavic M10 cassette body. One poster has already managed to alter a shimano cassette body slightly and hang an 11th cog.

I have two bikes; one with 8 speed and one with 10; they both shift about the same and there is no difference in the time it takes for maintenance, adjustment, etc.

I don't know if they are working on anything bigger than the current 10 but my 8 speed with a triple crank has all the gears I need. My 10 speed with a compact crank also has all the gears I need; my rides are mostly flat with some hills and some fairly steep but short climbs. If I was going to do a lot of long and steep climbing I might change the freewheel to one that would give me a couple of lower gear combinations.

I ride both 9 and 10 speed bikes, and if anything, the 10 speed shifts a little faster, but it is such a small difference that I can NOT rule out my own perceptions as 10 is better...

Maintenance wise - no difference. Same theories still apply,...

My 10 speed Dura-Ace is way better than my 9 speed Ultergra, but it is 5 years newer. Is it the age, 10 vs 9 speed or Dura-Ace vs Ultergra? I am not sure, but it is a significant difference.

9 speed is in sunset mode. You'll still find parts for years, but it will get harder and harder to get what you want, when you want it (or at a decent price.)

10 speed in any flavor works great.

every time I work on a 9sp D/A bike, I'm disappointed in the feel of the lever. it just feels like crap. every time I work on a 9sp Campy bike (Chorus or Record), I'm blown away with how good it feels.

to me, 9sp Shimano feels like crap...the shifters...ugh. even new. Shimano 10 wins. however, nothing feels as good as 9sp Campy. but that's just my opinion.

after taking my buddys new ULTEGRA SL around the crit track im completely sold on how a brand new 10 setup feels to a used 9 .... its just silky.. shifts clean....