Mindboards

I'm brand new to Lego, Mindstorms, and robotics in general, but I plan to make a hobby of it. Forgive me if my questions don't make much sense at this point; I expect to learn more fairly quickly.

I just purchased a NXT 2 set and plan to grab up an EV3 when they land. My questions are mostly about acquiring additional parts. I've read on thsi forum that Bricklink is a great source for parts. However, I also see lots of "grab bag" type offerings on e-Bay and wonder if those are legit parts or knockoffs. Does it matter? Are e-Bay prices better than buying new or used from Bricklink?

I don't know what type of things I will end up liking to build, so for now I'll try and collect some parts that will be generally usable. I'm thinking gears, beams, etc. I assume that motors and sensors will also be pretty handy. Will there be a new type of motor with the EV3 or will the motors be he same as in the NXT 2 system?

Are any of the Technics kits (actual things to build like trucks and cars, not parts collections) going to be useful in building various types of robots or are the Technics kits too specific? Are any of the Technics kits particularly useful in conjunction with Mindstorms robots, e.g., building robots to interact with a Technics vehicle?

Anyway, I appreciate any help you care to offer.

I prefer Bricklink to eBay. For me, Bricklink is easier to find the specific parts I need for a project. Check the
feedback for sellers, but I've placed over a 100 orders on Bricklink, and had problems on only one order, and
that was a misunderstanding and resolved after a few emails. I also order parts from
<http://www.legoeducation.us/>. They have a little different assortment of add-on parts than Lego.com.
Regarding what parts you may need, checkout <http://www.nxtprograms.com/index.html>, and the book
Creating Cool Mindstorms NXT Robots by Daniele Benedettelli. Nxtprograms has some simpler robots, and
Benedettelli's book more advanced robots, but both will give you ideas for parts. And I found some good
ideas for writing programs at both of these sources. And if you decide to mix Technic and NXT motors and
controls, there are some ideas at <http://www.nxtprograms.com/extra/PF_remote/index.html>.
Howard