I think you'll be much happier with a newer unit and you can still connect the monitor from your desktop if you want to work on a bigger screen.
I got a refurb'd HP Elitebook 8440p for $300, it's about a 3 yr old corporate class laptop with an i7 cpu, it's faster than anything where I work so I use it there.
I liked it so much that I got one for my wife (but her's is an i5 cpu).
I suggest shopping for refurb'd corporate class laptops that have been returned from lease. At the Intel plant I worked at, they replaced laptops every two years so I'm guessing they leased them or got smoking deals from HP.