I'm thinking about waiting for Haswell too. Ivy chips may drop slightly in price when Haswell is launched and if there is an ivy/sb like gap in performance I may go with ivy
Haswell is a new architecture rather than just a die shrink so it will offer bigger gains than Ivy did over Sandy; with that said however, Intel are increasingly focusing on power efficiency and integrated graphics so the gains will likely be smaller than we have been used to from previous architecture jumps.