I just put an Intel X-25 in my MacBook Pro and it's an improvement in a few places, but not a panacea.

It really improves boot and shutdown. This Mac starts up almost instantly. Shutting down takes only a few seconds.

It improves compilation of native code a bit, but not a lot. Macport installs are slightly faster. It doesn't really improve Java compiler results.

It also helps when you're running your machine at its memory capacity. I never hit swap hell anymore.

It does improve things, but I wouldn't trade the 2.6GHz CPU in this for the much-less-powerful 1.8GHz CPU that's top of the line for the Air.

Seconded. I have the X-25 my MBP. It is probably faster than what apple is putting in the airs, but I haven't checked. 2.33 GHz c2d, 3 GB ram. I still have a lot of trouble doing things like heavy multitasking, full screen web video or viewing pages heavy in JS/Flash.

SSD isn't a cure all. It's good for booting up, loading large applications, and when you're low on ram.

Actually, the 13" Air has an option for a 2.13GHz CPU.

Why not just install an SSD in your current MacBook? They're not too expensive these days, and the performance improvements are definitely worth it.

I installed an OCZ Vertex II in my 13" MacBook a little while ago and it made a big difference. I actually benchmarked the machine at each step of the process:

http://thingsaaronmade.com/blog/hardware-upgrades-for-develo...

Makes sense, although I'll be surprised if Apple doesn't switch all their laptops to flash storage in the near future. Ideally they'd keep the MacBook Pros the same size and ditch the DVD, so you can have both flash for the OS and apps, and a large HD for data. And post-2003 external storage options would be nice too...