Maybe I'm just a laptop noob, but I think my Inspiron 1520 is pretty decent (except the LCD, which is rather crappy). Many of the older Inspiron weren't as nice, though I'm not sure about the newer ones.
The Studio line is certainly a step up and the Latitude line... well, they're really nice, but the price tag isn't. My aunt has one of those ultraportable Latitudes for work, and the thing just feels solid and so uber nice. I looked up prices and I just can't imagine getting one for myself (not yet anyways).
Asus laptops are pretty popular. They typically have decent specs and very reasonable cost. Build quality probably isn't as nice as the Studio, but it's not too bad either.