Kudos to the OP for resisting the RDF and hanging onto his iP1 for so long! The shortage of ram is why I upgraded to the 2, and the double ram and retina to the 3.
I was being lured by the 4 (It has double the processing power and a better wifi antenna! Better FT camera, too!), but I think I'm going to sit this one out. I don't think I've ever had an experience with it so far that's left me wanting. Same might go for the iP5, whenever that's released. It'll have to be more than a spec increase and a case redesign to get more of my money...it'll need to have blow me out of my socks performance or features.
I seem to remember the iPad being described as an 'internet appliance' a few years back. And that's what it may end up being to most consumers: most people are unconcerned that a new coffee maker with new features is being released unless their old one quit working.
It wouldn't be surprising if we're about to reach the market saturation point soon, where everyone with the disposable income who wants an iPad already has one. Apple has to crank out new models year after year (or maybe bi-annually, who knows) and sell at least as many as they did the year before or their stock will take a beating. I almost feel sorry for them.