are you sure your existing software will not work? I have had Vista ultimate for about 3 months I use Irfan View, Serif Photo plus and Picasa for various things to do with pictures All of these I had using XP before Vista and have had not problems after updating. The only thing I have not been able to update drivers for to date is a Mustek USB scanner as I only use occasionally I can plug into my husband's PC which still has XP.
I would wait and see rather than spend on new programmes you may not need