I use a Wacom digitizer tablet for Photoshop, Illustrator and other programs like it, I also use touch pads like the Apple Magic Pad, and of course mice.

But I never could get the hang of using a trackball.  To me it always felt uncomfortable.

they do take a little getting used to, but once you do, it is very hard to go back to a regular mouse. I used our laptop when I went back to school and had a mini mouse for it - that felt awkward for me, LOL.

I have used a trackball for so long now it has become second nature

this is the one I use: http://www.logitech.com/en-us/product/trackman-marble
works for both left & right handed folks and the slim profile saves space (i have a small desk for one computer) I find I have excellent cursor control when working in Photoshop, and other programs, and it is quite easy on my hand. I also have a Kensington version that was given to me that is very similar hooked up to the printer computer, but it has a wider/shorter base (not as comfortable). May pick up another Logitech to replace it.

the one that Tin has, has more functionality than mine, but I find that style awkward to use.

But the thing is, I don't want to have to move a mouse around - with a trackball, you only roll the ball, the rest stays stationary (great when you don't have a lot of space to work in, and it is less stress on the hand)

Exactly!! My friend who gave me the old tack ball works on a computer tyicaly 10 hours a day. Between work and personal use. He also had shoulder surgery so ergonomics very important.
Tin

But I never could get the hang of using a trackball.  To me it always felt uncomfortable.

but the thing is, I don't want to have to move a mouse around - with a trackball, you only roll the ball, the rest stays stationary (great when you don't have a lot of space to work in, and it is less stress on the hand)

So what does one do when the battery needs replacement... one buys another mouse.  The mouse I got is the Razer Ourboros. 

This is also a wireless mouse, but can also be used as a wired mouse, by simply unplugging the USB cord from the charging dock and plugging it directly into the mouse.  This particular mouse is aimed at gamers, but I think it's awesome for just about anything, including accurate drawing and CAD work.  It's also very configurable not only in terms of button assignments ans such, but in terms of ergonomics.  It has side plates like wings that give it a very "planted" feel, the palm rest can be moved back and forth to stretch the length, and can also be raised to suit your hand position.

All this and it looks like a transformer spaceship.  Check it out, I highly recommend it.

http://www.razerzone.com/gaming-mice/razer-ouroboros

Tin

yours will be much more compatible having the scroll wheel.

FWIW - Blender is great for tweaking existing stl files - I haven't really found anything else that will do what it does (maybe Meshmixer? but not well enough versed in that yet to make a good comparison)

Tin

don't let it scare you. LOL and there are plenty of you-tube tutorials out there you can pick up the basics from.

I did watch a bunch of videos awhile back does not seem to scary . but I have heard the warnings to stay focused and stay off the rabbit trails.

the track ball I have is a hand me down not sure if the switches work may need a rebuild  but it does have a scoll wheel built in.

If you focus on just mesh modeling, Blender is not hard to use - don't let it scare you. LOL and there are plenty of you-tube tutorials out there you can pick up the basics from.

Tin

I never worked with it enough to master it, so I promised myself I would when I had the chance. I highly recommend splashing out money for a month or two and joining CGCookie. It's a coherent, step-by-step series of tutorials. You could whip through all the mesh tuts pretty fast. You can get some pretty dodgy and piecemeal advice from YouTubes (though I hit them up all the time for quick questions).

Sculptris has a reduce brush for simplifying geometry, which I use heavily. My current machine is fairly strong, but I really don't think the program has a high overhead if you watch your topology. It's really best for organic shapes, though -- sculptural things. For hard surface modeling Blender is your pal. And since you'll need to learn Blender anyway...

Oh, and Blender has Sculptris-like tools built in, I just don't find them quite as intuitive.