I have been using a HP dv9730us laptop. Bought since March 2008. So far sent back to HP twice because of disk drive problems (and motherboard problem - overheating). The machine works well for trading. But the reliability is a bit of a concern to me now. I also had used an IBM T-43 thinkpad laptop (company assigned) for about 4 years (since 2005). That was a robust machine. No problem experienced throughout the years.