I would NEVER do video editing or real photo work in a VM. Honestly - it's not a bright move. VMs are great for many things, but they are not designed for the intensive work and disk access that video editing entails, nor some of the ram hogging, etc. Plus, in a VM on a dual core machine, the most you can really allocate of your processor is a single core otherwise you run into synchronization problems and issues with competition between the host and client for cpu time (if you do some searching at VMWare, they don't recommend setting dual cpu setting on machines with a single dual core cpu - they only recommend using multi-cpu settings on machines with quad cores or mulitple cpus with dual cores)
If you have vegas, and plan to use it - there is no real reason to buy a Mac if all you're going to use it for is photoshop. If you were planning on using iMovie or Final Cut Express or Final Cut Studio - then it would be worth it.
I do have the predecessor to the 13"MBP (the 13" MB unibody 2.4GHz no firewire) and have edited SD and 1080i HD video on it. If it were going to be my only machine, I would have gotten a MBP w/ dedicated GPU and video ram rather then a system with shared video ram. The 13" does work for editing, but I enjoy my editing time much more on my main machine (Mac Pro). If you do a search for posts from me on this topic area, don't remember how far back, I reported back to someone my opinions on Final Cut Studio on my MB 2.4GHz Unibody (9400m w/ 256mb shared ram).
I'd seriously though think about what you are purchasing and why - if you already have and plan to use Vegas, and have no intention of moving to Premiere CS4 or Final Cut for editing video and if most of what you do is video editing, you'll be spending a lot of time bootcamped into Windows to get the full speed of the system - at that rate, you may as well purchase a Windows based laptop rather then purchase a Mac and then have to Purchase a windows license to use bootcamp.
Oh, and if you're curious - authoring doesn't take the big hunk of time - it's the rendering and transcoding that is the brutal part. Rendering isn't bad if you do it frequently enough on the 13" laptop so you don't have like 30 minutes of source to render out. Transcoding - like using FCS Compressor - that will push the cores to the limit and will take a long time (I do most of my heavy transcoding on my mac pro instead of my 13" 2.4GHz machine)
