Depends what you want to do with it... from my experience of over 10 years in the IT field...
Toshiba - very good laptops, for many years they only made laptops and it shows. Downside is it shows in the price as well
Acer - I have had several Acer laptops and netbooks.... whilst well specified for the price, I have found a massive variation in build quality, if you get a good one you have a rock solid machine that will last for a long time, if not you have an absolute dog you will hate for ever.
IBM / Lenovo - I have never actually paid for one of these with my own $, but have had them forced on me by employers. On the whole, not bad machines, fairly well specified with reasonable battery life. No real complaints.
Dell - again, never paid for one myself, but had them forced on me by clents... I dont like them.
HP/Compaq - get the right deal and you have a well specified machine for a good price, alternatively you could pick up an overpriced hunk of crap.
Other makes - having not really had any exposure, I cant in any honesty offer a valid opinion.
If it were my $ I would be looking towards the best Toshiba I could afford from the Tecra or Satellite Pro line.
Please feel free to PM me for more advice if you like.