Nicholas you will be best using a 32bit OS no matter which flavour. I say this because many drivers for astro hardware do not get on well with 64bit programs (software developers need to move more quickly on this). I use Vista 32 on my laptop as that is what it came with and it gets on with all the stuff I use. Guiding, capture and grunt work is done in MaximDL. I use starrynight pro 6 for planetarium duties and about half a dozen other programs including CCDStack, CCD inspector, Pempro, Maxpoint, CS4, AIP4win and the list goes on. Your laptop does not need to be a hotrod, just capable of handling the capture and guide duties. Helps if it is easy on the batteries as well unless you have access to mains power or other sources. Best to do processing on a PC as they are far better at this then laptops so if you are going to hot anything up make it your PC. If you go with the synta EQ mounts you may want to look into EQMOD (
http://eq-mod.sourceforge.net/imgindex.html). I have not used it myself but folks around here swear by it. Oh you will also need to download and install the latest ASCOM platform (5.5 I believe).
Mark