For just $1644 shipped after rebate, you could pick up a previous-gen MacBook Pro, which retailed at $2500. It features “Intel’s latest 2.5 GHz 45-nanometer Penryn series Core 2 Duo processor (with 6 MB L2 cache) — also helps to reduce power requirements and save on battery life.” Product page.
Put in perspective, it would totally spank the similarly priced $1599 MacBook in benchmarks, and keep up reasonably well with the new model. Amazon is offering the rebate on regular last-gen MacBooks too, if you wanna go that route.