Sure it will. Even with the Natty, you can select the "Ubuntu Classic" Login-Option and have GNOME back. I've used the normal version of Ubuntu Maverick and I'm using Natty on my netbook without any issues. Also battery life is normal.
Good luck out there =)
P.S.: If you're still going to buy a netbook, try look for the ones with AMD Fusion APU. It's like having a notebook in the size of a netbook =) Also watch out for battery lifetime. Don't trust on advertisement battery life. By the way, 3-Cell batteries are worth nothing. I've got a 62Wh (unfortunately, after some accidental full-discharges, now 54Wh) 6-Cell battery that holds my netbook for 6:30. And it doesn't even have SpeedStep! =)
Oi, I've re-read your post again. I've read somewhere that the ION is having some issues with Ubuntu, and nVidia isn't supporting it, 'currently'. I suggest you to google for more info and, if I'm right, go for another model. Good luck!
Media Center PC
: AMD Athlon 64 X2 5000 | 2GB DDR2 800 | ATi Radeon HD3200 | 320GB HDD SATA II | Realtek ALC889A | Sony Bravia 46" 120Hz | Ubuntu Maverick
: Acer Aspire 1410-2287 ~ Intel Celeron ULV 723 1.2GHz | 2GB DDR2 800 | 250GB HDD | Intel 4500mHD | 11,3" HD LED | 6:30hrs Battery | Ubuntu Natty