I hate dells, but I won't go there. If you want a PC laptop I strongly suggest you look at someone else. An Asus or HP Business class. If you want a Mac then get a Macbook.
I've had 3 Dell's in the past 5 years without any issues, of course I sold them within 6 months so I can't speak for their longevity but while I had it everything was fine.
A couple of years ago I wouldn't have touched a Dell with a 5 meter pole however since working in IT in a company which buys only Dells I think there not bad. I wouldn't buy a Dell desktop (home builds all the way!!!) but I would consider a Dell laptop.
Although HP may be worth a look as there stuff seems pretty nice and very good value.
[edit] Oops after some googling I realised the 518s a desktop, always thought of inspirons as laptops and dimensions as desktops, I'd certainly reccomend a desktop over a laptop if your not bothered about the portability end of things. I'd only reccomend a pre build if your not comfertable with building yourself (it's really not as difficult as it seems and we can guide you through it). [/edit]