I am a long time mac user, not a new switcher, but I am a web developer on a mac. If you are going to heavily rely on VMware to run all of you windows apps you might want to grab a pro or the top of the line macbook, the bare minimum is to juice up the RAM. I have an older white macbook and I love VMWare, but just for running on operating system at once, I usually have a ubuntu server going and when I try using a winxp system it does get a little sluggish on the computer.
In terms of mac version of the software they are equally good, MS Office for mac is usually pretty responsive and doesn't crash. In my experience massive excel files sometime bomb out excel, I'd say the PC version was a little more stable. People have also said the newer version of Adobe CS seem to run better on PC then mac. I have not really had a problem, though. I never heard of mac version of UltraEdit, SQLYog, WinSCP, Camtasia Studio, Although for Camtasia there are some decent mac screencast recorders, but not to my knowledge ones as feature rich as camtasia.
I know a few people who have asked for my advice for buying a computer and being a good apple fanboy, i've recommended macs, once they got the hang of it and the little differences they've really liked it.
I know for me having access to the unix underpinning/programs is a great thing that has help me as well as being able to install pure linux programs, pending dependencies and all that. I've gone the VMWare route for running my windows things and not using boot camp. If I wanted to use the windows side of things for longer periods of time I would use that setup.
All that said, with more market share that macs are gaining it's great using one because most of the system is well thought out and can be pretty powerful when you need it to be. I can develop sites on my system like I am developing on the linux box I am going to deploy to, test sites with in safari, firefox, ie6, ie7 and have a generally secure computer that I can kill any process or program that is freezing up on me.
Just my thoughts