For me I find ask UK a better bet, more buying customers but you do have to pay for it, hate it but it works.
I have noticed a climb in hits from AV nothing to jump up and down about but an improvement.
I am considering espotting at present for Yahoo since the uk results are such a mess.
Just about zero from anywhere else but that may just be my industry.
I do believe that you have to think about and experiment as to which search engines and Directories your typical customers use.
Espotting is worth it I think. Cheaper than overture still.
Otherwise Me too, for Google! Freeserve and Ask both bring in sales.
George