Depends, my wife loves the netbook. You can surf the web, do a tiny bit of photo editing, type on word, that sort of thing, email.
But if you have any intenesive programs, like photoshop, the netbook is out. Not only that, to get the performance we wanted out of a netbook, we had to dump windows and go with linux, which in our case was fine, since we run a box already.
Bottom line, if you just want a super portable internet/email device and can't stand your PDA, the netbook rocks. but as far as replacing a laptop/desktop, for most users it will not do.
And don't sweat the lack of an optical drive...unless you need to install something from a disk, obviously, we have a sub optical drive, but sparing that, you can also use a networked drive.
I recommend the samsung six cell netbook, works about 6-8 hours of general use, has a cam and net adapter built in and is available in stylish pink(grumble).
With the prices of netbooks/laptops, I just think about what you want to use it as. Laptops have certainly come down in recent years, so you can normally get one for well under a grand, the laptop we looked at when getting this one was 750 and was pretty much equal to our desktop(minus the graphics card), but we just wanted this for net use and travel(its amazing how light these things are).