1. Mac allows you to dual boot into Windows as well as Mac OS X using the free BootCamp. If your work requires you to use Windows, you can install Windows onto Mac and then boot into Windows natively. You can also install Parallels onto Mac OS X so that you can run Windows on a virtual machine.
2. Prices for Macs are getting very competitive nowadays. Overall, the prices of Mac are still a little higher than PCs, but considering that you have the ability to run both OSes, it is a small price to pay. Moreover, the quality of Macs are way more superior than most commodity PCs.
If you are looking for a Mac notebook, I recommend you go for the latest aluminum 13-inch MacBook, which costs S$2088. If you are budget constrained (who is not?), then you can go for the older (but still trusty) white 13-inch MacBook (S$1588). I have been using the white MacBook and it has been serving me very well for the last 1 year.
Moreover, if you are a student or educator, you can get some nice Educational Discount at http://www.apple.com/sg/macbook/.