One thing you’re going to notice real quick with tablets, especially with illustration versus other applications such as photo manipulation and vector work, is that the surface of most of them is going to be too small to draw from the elbow instead of the wrist.
I currently have a Bamboo Capture from the CTH series as a backpack beater, and the smallest Intuos 5 for desk work. I’m a graphic designer, not an illustrator, so I operate well enough with a smaller area, but I can suggest some that I think would be better off for you.
The CTH and CTL (Splash/Connect) series Bamboo tablets share the same exact specifications. The CTL series is cheaper, however. Take that as you may. It’d seem the Splash and Connect are the same exact thing, except regionally named; I can’t actually say much myself on this, but the specs are exactly the same. The CTH series, however, does have a larger version with an area of 8.5" x 5.4" instead of 5.8" x 3.6", but that’s the only difference, so wether or not you want to justify that purchase is up to you.
The Intuos 5 has double the resolution (measured in lines per inch, 5080 as opposed to 2540), doubled tip sensitivity (2048 levels instead of 1024), an accuracy of +/- 0.25 mm instead of +/- 0.5 mm, and also pen tilt recognition, which the other series doesn’t possess at all. Problem is, smallest version is $200.
I guess your conundrum with these suggestions is wether or not you value surface area or sensitivity. The Create can be bought on Amazon for ~$150, and has the large surface area, but less resolution and sensitivity, but the smallest Intuos 5 has it, but it’s smaller and goes over budget. I don’t know how you illustrate, larger elbow movements or more intricate wrist movement: if the former, Create, if the latter, Intuos 5. With larger movements you don’t necessarily need the crazy precision, and with smaller movements you’d really appreciate the added sensitivity. When it comes to pressure levels, both oughtta be okay, especially with someone new to tablets. Again, it all comes down to your illustration style. I’d make an educated decision based off of that.
All of these tablets will work with Manga Studio, but wether or not they work with Windows 8 is a question I can not answer. I’d assume so, but I’d do some research into that.