Most of the top brands are OK now, most have got over their hardships with leadfree now, even Tosh who were one of the last to overcome it.
My favoutites, in no particular order, are Toshiba, HP (business, not consumer range, ie, not Pavilion), and Dell.
The ones I'd not personally buy are ASUS, Acer or Advent.
For basic uses, try to get a Core i3 based one - AMD are behind, and Intel Pentium, Intel Core/Core2 is older technology, and Celeron does start to show its limitations now. i3 is within your budget if you shop around, esp as some shops are selling their older generation Core i3 and i5 to make way for new generation 'Sandy Bridge' i3 and i5
Memory isn't hugely important - anything 2Gb or over is fine for general Windows 7 work (email, browsing, Office Productivity).
For laptops, I tend to avoid disgrete graphics, unless absolutely necessary (in which case, maybe a desktop is better option), due to thermal requirements.