Micro Mart Issue 921 has a table detailing the differences between all the versions. Some highlights:
HOME
Standard Basic Prem
32-bit CPU support Yes Yes Yes
64-bit CPU support No Yes Yes
Max RAM (32-bit rig) 256Mb 8Gb 16Gb WTF!? 256mb!? 8gb, 16gb!? Eh no, 32 bit = 4Gb max, no more.
Max RAM (64-bit rig) NA 8Gb 16Gb
# Physical CPUs supported 1 1 1 BS again
Max screen res 1024x768 any any
Aero glass No No Yes
DVD video auth No No Yes
Media centre No No Yes
Network connections 0 5 10
Internet sharing No Yes Yes
Migration fm XP No Yes Yes
Business versions offer more RAM (128Gb+!!), multiple physical processors, web server (presumably next version of IIS - if you want a web server for a Home version I presume you'll have to use Apache).
I will prob go for the Home Premium edition - but not at £185!!