I'm a veteran Windows user (3.x to Vista and everything in between) but I'm still a n00b when it comes to *nix environments. I worked with linux on and off for about a year during my college internship (php/mysql web development) but that was mostly ftp/webdav work or file maintenance through cygwin.
I won't be able to move away from MS on my desktop as I'm a Software Engineer by day for a company using ASP.NET/C#. I am considering putting a Linux distro on my personal home server though and I am also considering a Mac for my next laptop (a fact for which I'm taking a lot from my coworkers who I'm convinced just hate Apple since they dislike even ipods).
Welcome to the forums!
I got my start on Linux with a $30 second hand PC and then migrated my home network to it after my confidence grew.
So maybe you can still get that Mac and do Linux!