I have over a dozen handpieces that I use. Most have collets, because they are dedicated use tools. The general use handpiece I use all day long is the standard H.30. You can use it for any bit or burr up to 1/4" shank.For metal work, get the heaviest duty motor unit you can afford. The bigger the motor, the better it will cut/grind/etc. The 1/3HP TX series is really worth the extra money - about $50 more and twice the power.
I would suggest a TX package that has the motor, foot control, and the H.30 handpiece. They run about $225-$250. Don't waste your money on the packages with a kit of burrs and stuff. Most will not be used. Buy the burrs you want individually. Carbide burrs are by far the best when available....spend one cry once.