Could you stretch to a BMW 645 convertible? If you need four seats any beemer ragtop might fit the bill.
Otherwise, a Boxster would be an excellent choice, commuting just not an issue.
Do try an Elise if you can - as has been said, 4 cylinders can be more than enough, and for someone really interested in driving there is nothing more involving on the market.
Otherwise, my friend loves his S2000 - they're very good value in Europe at least, but the Honda remains a division below both Porsche and Lotus in terms of hooning about
