this Compare site from Microsoft;
It's going to be personal choice of course, but XP Pro gives more networking features and more Administration options. I have a home network so Pro seemed the better choice for me.
But in my view the important thing is to buy as much RAM as you can afford, (I have 2 GB), and as large a hard disk as you can afford, (220GB here).
Also, a large LCD or CRT monitor if you can stretch that far.
I want to buy a another computer for the usual home use things, but primarily with most efficient operation for games, music and Net searches.
New ones here (UK) are mostly sold with "XP ... SP2", and Home can be upgraded to Pro before purchase for about $80-$100 on OEM models. (One assumes an adequate overall specification for either to work satisfactorily.)
Not knowing the difference, is there any advantage for going for a Pro version?