I don't own an AlBook (I have the last BlackBook) but I am applying for a job in an Apple reseller and I have had a go with the AlBooks they have on display and wow...
Admittedly the screen is a tad disappointing. I mean yay for LED, finally a solution to the uneven CFL backlighting, but I still think the colours are flatter than they are on my BlackBook. However, the glass display is amazing and I am glad they incorporated the black bezier which makes working on film or images, or even just plain using the hell out of the machine so much more pleasant.
The trackpad. I
hated it at first but it has grown on me. I guess I just wasn't prepared for the usefulness of multi-touch. I just wish they hadn't killed the button... I
like having something separate to click on. This actually reminds me of the joke of the Pro and Mighty Mice, they were mice with no buttons at all to annoy the Windows two-button world - now we have a trackpad with no button neither.
The keyboard. I love it. The backlighting is so subtle and useful. I wish my BlackBook had it.
The speakers... well they're certainly an improvement on the old generation of MacBooks but they're still nowhere near as powerful nor as rich as the MacBook Pro (any generation).
So... what are my favorite features? I love the sleek look of it. I mean man is that a beast of a notebook! Its damn near fantastic. No more fingerprints... sorry BlackBook

. I love the keyboard too. Its sheer brilliance.
One thing I really have a problem with...
I want my FireWire back!