No reason for portables to have optical drives built-in these days IMO – mine get barely any use any more (and I’ve been pondering reusing the space to have a SSD + big HD setup on my Macbook). Have a USB one on your desk for the times you need it.
Air looks great, going SSD only makes a lot of sense (especially if you’ve used any ultraportable, including the old MBA, that uses a dog-slow 1.8″ 4200rpm hard disk) but I’d find it hard to live within 128GB unless it’s a secondary machine and I had an iMac or something with my iTunes and iPhoto libraries on.