ahhhhh - the classic "Mac vs. PC" question.
this can sometimes be classified as a religious question depending on who you ask.
how savvy are you on a computer, first of all?
do you know how to use a Mac OS? Windows?
do you know how to troubleshoot either?
someone once told me, "Macs are for people who don't care how their computer works, they just want it to work." it's somewhat true, but don't tell a true MacAddict that.

i'd look at the software you'll be using for work, and see which, a Mac or PC, supports that software best.
Pauline, we too have a Vaio sitting in our living room. it's our "surfin' machine." small, light and for mild use. it only has one USB port, but more can always be added.
My personal preference for a work machine would be a Dell. i have a desktop at work, one in my office at home, and chewed thru one in college. They've always served me well, and the service is great.
we use an external hard drive to back up our files. if you travel, you may look into the
memory sticks. these i wouldn't use as a permanent back up solution, but good for temporary back up and travel.
well, there's my two, maybe three, cents.
good luck!
Lately it occurs to me
what a long, strange trip its been