To a certain extent, it depends on what you're used to and what you want to do with it all. I've always found the Macintosh system generally easier to use and more powerful than the Pentiums, especially since I'm an artist. Although I have access to both platforms, I do 99% of my music and Adobe work on the Mac.
As far as specific programs go, Internet use is significantly better on the Mac simply because of the huge number of viruses that just don't work on the Mac which makes surfing that much more safe. Of course, there are the occasions where I can't access a web site because I'm using a Mac, but so far the only one important enough for me to remember was when I tried to lodge my Aussie Tax Return on the net... then I had to use a Pentium.
As far as Messaging goes, MSN messenger will always be better on Windose (but you should expect that since its Micrsoft's program), but it works fine for me (I just can't see people's pictures). I am starting to use Skype these days and that works great.
Music and Art, you'll always find a disproportionate number of professionals use a Macintosh for these applications.
Playing and Creating media files? Theres a couple of .avi and .mpg codecs that my computer just doesn't understand, but they are scarce enough to not bother me. Other than that, I can read all file types or find a translator. I used to use the Pentium computer for Hacha and split files, but the MacHacha does them all very nicely (once again with a few exceptions, but not enough to bother me). The only major file type I can't seem to export as using Quicktime Pro so far is .wmv, but it does .rm .mpg .avi VCD and a whole lot more I've never seen before.
The draw backs of the Macintosh are getting fewer and fewer these days. Now they read virtually any PC file, network incredibly easily with each other and/or a Windose network... my father uses a G4 iBook at his school and dispite the rest of the school being PC based, he almost never has to bother the IT Techs and only uses Virtual PC for the school's Marking program.
Of course Macintosh's are generally more expensive than PC's, but I'm not going to buy something that's cheap if its not going to do what I want it to. You still always get what you pay for. The largest draw back in most people's opinion is the fewer amout of software for the Mac, or the time it takes for programs to be ported to the Mac after a PC release. This doesn't worry me though because I tend to use programs such as Sibelius, Digital Performer, Max/MSP and Metasynth... all of which tend to be released on both platforms simultaneously, or are actually Mac-Specific.
Some more news though, in the not to distant future (within the next 2 years I think), Apple are actually changing from the Motorolla (G3/G4/G5) processor to the Intel Chip. Though I've got mixed feelings about this, this will mean that most of the drawbacks to the Mac will be removed. By having an Intel Chip, when you buy a Macintosh computer you will have the choice of installing MacOS, Linux or Windose (on normal intels you won't be able to install a MacOS apparently)... and quite possibly, Windose may be able to be operated within the MacOS system similar to the way 'Classic' (MacOS9, the old version of the MacOS) runs. The time porting programs will be significantly reduced and may not be nessicary if previous suggest comes true.
Thats all I can think to say at the moment. Hope it helps.
