The iPad 2 is great, but the one thing it didn't get upgraded from the original was its screen. According to one analyst, that might be changing later this year.
According to FBR Capital Markets analyst Craig Berger, Apple is looking to release an "iPad 2 Plus," with the same guts as the normal iPad 2 but with a screen approaching the resolution of the iPhone 4. That'd be nice, but also a pretty weird move from Apple, who doesn't go for incremental products like this.
I think it's a safe bet that the iPad 3 will have a higher-res screen. Will there be a half-step iPad in between 2 and 3? Maybe! We'll just have to wait and see.