I use both Windows and Mac for different things. I have been the System Administrator at the school I teach at since the beginning of the year. We have ~50 Macs on the network and just a few PCs. (I'm typing this on an HP laptop with Windows Vista, in the morning I'll check it on a Mac PowerBook with OSX 10.5 I use the platforms interchangeably)
Really the main thing is to get used to OSX rather than Windows, there are more similarities than differences in the basic function of the operating systems. Mac always seems more...tactile, (for lack of a better term) in that things are done in a more direct way. For example, you install a program/application by dropping the download or item from it's icon into the "applications" folder as opposed to the windows "installer wizards".
As far as internet browsing goes there is really no advantage Windows over Mac. Unless a site is written specifically for Internet Explorer, which is no longer supported by Microsoft for Mac (this is rare and almost only found for certain official sites (Government, or Corporate. that use encryption, lately I've seen more of these encryption sites using Firefox.). In reality, use Firefox on a mac or PC...it is infinitely better at controlling popup ads and is a "lighter" program than IE.
Macs do have the major advantage of having virtually no malicious software written for them (Virus, Spyware, Adware, Trojan Horses). This is based on the disparity in usage more so than Apple software people being better than Microsoft's. This simple fact alone has made my job a lot easier.....I have all the students use Mac for any internet use. It is as foolproof as a computer can get in this regard.
With software, yes Windows does dominate. There is simply much more software out there for Windows. Look at your usage though...
What do you need? Are you dependent on a program that doesn't have a Mac version or equivalent? Mixcraft does not have a mac version that I know of, however....Macs come with GarageBand which is a very similar bit of software and is very powerful despite it's initial simple appearance. We've even mandated learning Garage Band in our Middle School music Curriculum. It's been a powerful education tool, we use music to help kids understand computers and vice versa.
Apple has finally permanently solved issues with windows compatibility, All new Macintosh computers are loaded with Intel Dual-Core Processors. That Intel processor can work with both Mac OSX and Windows. So I have a Mac at home that has both Mac OSX v10.5 and Windows XP spII. I have a few at work with this same setup so we can have school records in both formats since students transfer in and out from various districts that use varying computer systems. You do have to buy a copy of windows to run both, but it's really as close to perfect platform as is commercially available....you can do 95% on the safe and stable (virus wise) Mac Platform, then use Windows for things that are not Mac Supported. Since most of your web usage would be on the mac side, you would greatly reduce odds of malicious software wreaking havoc on your computer.
That said, us Mac System admins are being vigilant. With the popularity of iPod and iPhone from Apple, we are watching for malicious software written for these devices that could potentially infect OSX. So far nothing major has come on the radar.....but I've been installing Anti-Virus Software for the first time on the Mac network to stave off anything that may arise.
There is also the Unix/Linux based crowd. Unix/Linux is powerful and...almost all free of cost, no major virus threat etc. The Caveat is that it isn't commercially supported so if something happens, you're on your own. Which doesn't appeal to most casual computer users. Mac OSX is based upon Unix but not 100% compatible with all the versions of unix/linux that I know of.
If you have files that need to be moved from your PC to a potential new Mac, that has gotten easier as well. For the most part file types have become more generic across all computing platforms (thank the internet for that) Images are often in JPEG or GIF. Audio in MP3, Video in MPEG etc. These files move across platform without any messy issues like we had 10-12 years ago, when Macs used IMG files and Windows used BMP files for pictures, these weren't easily shared. If you use a program like Microsoft office for word processing or spreadsheet etc....there is a mac version and the files will move over and open in the mac version. (also check out freeware MS-office compatible programs called abi-word or Open Office, it has both mac and windows versions)
j.