IMHO, 80Gb hdd for a laptop is more than sufficient, 120Gb is ideal. Above that, it will only be a waste. Before you are able to use up the 120Gb, your other laptop parts will have worn out. I am talking about regular use of office documents, not so many mp3s (1000/2000?). Also, external drive/flash drive is so much cheaper nowadays that it cost a dime to a dozen.
I'd rather spend the extra money to add more RAM, go to the highest if possible (4Gb?), 2Gb is just enough for Vista. One gig or lower on RAM, your laptop will go painfully slow on Vista. Trust me, I had it. I had 3 Vista still on the box that i haven't even open yet. I had to downgrade several laptops and several PCs to XP.
WinXp is still one the most versatile windows version yet if you know how to set it up properly. For Vista, there are still many compatibility issues, one of the known issues i have dealt with is with the accounting software called Solomon (a microsoft product too!!).
FYI: I have two toshibas at home: satellite pro and the tecra. Both have no problems. One is 15" (5 years old), the other is 14" (1 year old). My company has used Sony (not recommended), Dell (Ok), Toshiba (Ok), Fujitsu (Ok), and HP (Not recommended) and Compaq (Just fine). It is only based on my observation and personal experience.