S series is market position is 1 class higher than A series
s60 seem cool
although no original WA convertor
but can use the ricoh or other brand one (if i am not wrong should be 37mm) to make it to 22mm wide
S-series are better than A-series on the processor speed, meaning faster shot-to-shot, multishot, better menu response, RAW image, etc. Function-wise, they are similar. If price is not a factor, go for S-series. However, A-series have vari-angle LCD which is more fun to use. Having said that, A80's LCD screen is miserably small.
I'm currently using a S50...bought last year June. It served me very well and it's actually quite compact too. Features wise more packed than IXUS I feel...my S50 is my learning camera . S60 specifications wise resolved some of S50's limitations because of the zoom and wide angle increase - the 2 main things I struggled with S50. I find A80's screen a bit small to handle. I can't bear to part with my S50 so now saving money to buy a DSLR ;p . Hope this can be of help to you cosy .