Hi,
All of them should work - but I would choose the Western Digital - partly based on my own experience, but I also think that for the price it is better specified (ruggedness, etc) than the Samsung, Hitachi, etc. Seagate is good, but perhaps a little pricey in comparison. But be careful not to miss any bargains at the 120GB level - they are getting cheaper all the time.
Cheers,
Les.