I do 3D design and work with a 3D printer on a regular basis. We currently use Rhino 3D for designing our products and an Objet 30 for printing. For what it is the pricing for the software is reasonable, but the printer would probably be way over budget, but the detail is awesome. Here's a few notes about software and printers.
Software:
Different 3D software is designed for different purposes. We tested Blender 3D (free) first, but since it doesn't really have a proper system for precise measurements it was a no go for product design (though it's great for animation and gaming work). You CAN find patches that can help you with that, but it being open source it meant we'd be stuck with FAQ pages and no proper customer support if we got stuck.
Strata 3D was also quite interesting, but at the time it didn't have the STL support we needed (I have heard this has been updated).
AutoCAD, Solidworks and another similar programs have the advantage of creating different types of fill for your objects, but you lose some sculpting and modeling capabilities that you might be looking for. If your goal involves industrial design these two are by far the best.
Other "consumer" software (123D, Scetchup etc). I've messed around with these as well. While they're quite easy to get started with you'll quickly run into their limitations. Also, many of their UI elements don't really transfer to more advanced software so there could be some relearning when it's time to upgrade.
We ended up going with Rhino 3D. It's a nice happy medium for product design and sculpting.
Printers:
There are a few different types with pro's and cons
Extrusion 3D printers: These usually use ABS or PLA plastics that are heated and extruded through a hot head (think of it as a fine tipped glue gun) onto a motorized bed. They're everywhere, cheap, and so is the material. The detail was ok for what we needed, but if you're making small action figures or something with a lot of fine detail you may want to save your coin or at least take some time and learn how to get the most out of these. Also, be careful to avoid models that have a wooden or plastic printing surfaces. These can warp quite quickly. Best to find one with a heated aluminum bed. Your prints will be much more consistent.
Polymer Based: These ones are only really found for industrial uses so they are NOT cheap. Basically the detail comes down to how small the polymer grain can get........so yeah, pretty sharp. Some also have some impressive color capabilities.
UV 3D printers: When it comes to detail these are by far the best and are starting to get cheaper. They use a type of liquid plastic that solidifies when it gets hit with UV light. This is what we use at my work so I'll always recommend it first. Check out Stratasys for their full line up.
Hope this helps!