I would go with a digital driver, or a gecko.
Power supply I would get from ANtec dirrect. I guess Keling is giving peak rates and Antec gives continues ( same PS). I believe it is the PS 10N70 that is the same PS Keling is offering. If you want 1500watts get the PS 15N73. Either can have the 5v supply you need added just by getting a 15 dollar module from Antec (transformer is already wired for it, plus its cheaper from Antec). It doesnt really take anymore power to run a bigger supply anyway, and it will have better regulation. The 1000watt unit ( PS 10N70) will be plenty for you but if you start adding more axis or motor driven parts it would not hurt to have the bigger. It will only use what is drawn on it, at idle they burn very little. The Antec style supply is very cheap and easy to repair if something goes wrong also ( can fix it yourself and get the parts cheap, very few parts also).
Laztcam,, I will say its worth getting. Unless you plan to buy something alot better. Even then 75 dollars is nothing when looking at software and Lazycam is growing. You will be in on it for cheap. Its usable, but will get better.
Ballscrews will be better. No need for Handles at all either. You can run the factory screws for a while if you need, and maybe even be as good as you need. But ballscrews will be more accurate, and require less power from your axis motors. Again forget using the handles and hook direct to the screws with your stepper/cuppling setup.
Yo can read Hoss thread on his G704 ( in the benchtop machines section a little below this section)and the guys are going over ballscrews, price and where to get them. I have been using the Rockford double nut ballscrews but they have been using some others with good results and price ( the rockfords are pretty pricy). Getting a no backlass setup going will be worth the effort.
Hope this helps get your thread going a little anyway, maybe others will jump in when they get here.