Is it better to dual-boot or run a VM?

Dual boot is a waste of time. I describe it to people as "the 5-minute alt-tab". It's a pain to configure, and because you can't run both OSes at once, when you need the one you're not running, you have to kill off every app and reboot.

I avoid dual boot like the plague. VM all the way.

Or, just use a single OS that does what you want. Windows with Cygwin provides a lot of the Unixy stuff that most people need.

if you don't need the full potential of your graphics card for your Linux application, then Virtualization will certainly suffice. if you do, then native Linux is mandatory.

but don't let ZimmyDubZongyZongDubby scare you with his remarks. Wubi is a painless and easy way (and thus ideal for novices) to setup any flavour of Ubuntu in a Windows/Linux dualboot environment. install and uninstall Ubuntu as any other Windows application, in a simple and safe way.

Install windows, and run Linux in a VM.... but use an xwindows software like xwin-32 or similar to bring your linux windows forward to your MS windows desktop.

I think you'll like working this way, as you'll have terminal windows and be able to open more or less any non graphic intense linux app seamlessly. You'll be able to mix and match.

If you need more processor for running a game, you just shut down the linux VM..

VirtualBox, or VMWare Server should both work pretty well.