Should I upgrade to a MacBook Pro or cheap PC laptop?

I am a lifelong Mac user. However, I am starting to work at a new location whose software is only PC-based. I want to be able to check up on things from home, and therefore need “a PC”. I currently have a PowerBook G4 running Tiger, and I am still quite happy with it. Virtual PC is really, really slow, so I was debating whether to invest in a cheap PC or bite the bullet and upgrade to a new Mac. Any suggestions pro or con, and specific ideas for a cheap PC would be greatly appreciated.