Wacom's are an awesome bit of kit and I'd really recommend them but they're not essential.
Once you've used one you may disagree.
They take a bit of time to get used to but once you do you'll prefer them over a mouse even for general use to replace a mouse rather than just drawing and stuff.
I had a big old Intuos 2 and it was bullet proof but took up too much space on my desk.
The bottom end Wacoms like the Bamboo are fantastic and I was surprised how good they were in comparison to the Intuos and they're just the right size.
You'll find they speed things up no end and going back to a mouse will seem clunky and awkward.
Get one! You NEED one!