After two-plus years of PC's at work and nearly 20 years of mainframes before and with the PC, I bought a Mac mid-speed G5 with 2 Gigabytes memory, and haven't regretted it. I would recommend buy the most memory you can as speed is less important and memory working on larger files.
I've found Safari to be an excellent browser, and you can download Firefox or Opera for free. I design off Safari and use Firefox for testing Web pages. Opera is a user choice and I only use it for checking final pages because the interface and user controls suck. I've only downloaded a few shareware packages from Apple's Web site of third party software.
Unless you really like a PC and MS software (I don't and I can go on at length about it) you can do anything with a Mac, and do it better and easier. You can also import any MS file into any Mac similar package. For examples friends send Word document, and I just import them into Pages and work from there. The other advantage to a Mac uses unix as its OS, which if you're familar with is easy to work in terminal mode as an alternative.
Good luck.