iPad with retina display?
Maybe the right question to ask is: is current featureset of the gadget worth the money over the expected period (6-18 months) until the new version arrives ? If yes, go ahead. Waiting for better improved version may also mean you never get one as there is always going to be better version.

What works for me is skip-one, buy-one approach, getting every second update. You can decide whether you start with version one or two: I had same dilema with iPhone: I skipped the version one, bought 3G, skipped 3GS and now considering getting iPhone 4 when it arrives to Canada.

With iPad, I bought one right away as I waited for eBook reader that works for me and iPad is definitely one. I will very likey skip iPad 2 and likely get iPad 3 2-3 years from now.