The Iconia W looks pretty good, but it has only a 32GB hard drive and it weighs a little more. It states it has HDMI and 4 USB slots, but it isn't clear if that is an interface or built in. It does have an SD card slot, so you will be able to expand the storage. It doesn't say if it is SDHC (32GB) or SDXC (64GB).
Asus E-Slate:
Better processor (i5, dual core)
Weighs a little more
Shorter battery life 4.5 hours
SDXC interface
2 USB and 1 HDMI
Also has precision pointer
Win 7 Home Premium
Lenovo X220
12" screen, so really a small laptop
Battery life 4.5-18 hours, depending on the batteries
I do not understand the usefullness of it converting to a tablet. To me the usefullness of the tablet is that it is small and has no keyboard and it light. With the spin top, you still have all of the weight, and just have a touch screen.
Lenovo - Laptops - ThinkPad - X Series Tablets - X220 Tablet