In my order of preference:
1st-Legacy - Build-A-Droid
2nd-TAC - Coins
Tied for 3rd-Power of the Jedi - Force Files/Saga '06 - Hologram Figures
The following 3 tied for 5th:
Saga Collection - Stands
OTC - Stands
RotS - Stands
It's a no brainer the BaD parts are the best. For the value and variety we got a good many extra figures.
The coins were fun to collect. Some harder than others, but once you get a complete book of them, they look pretty impressive.
I actually liked the Force files. Neat little snippets about the characters.
The hologram figs were nice and some actually are decent enough scale for scenes. No not exact but their good enough. Also, they make for good mini chess pieces.
Of the stands, I'd have to say the ROTS ones were better in detail and color, though they could be a bit clunky and didn't al that well fit together. The other stands were bland and unimaginative. Yes, easy to pose figures, especially army builders, but they just didn't have a value to them, for me.
If I had a real choice though, I'd rather they do away with those pack-ins and knock the price down by a dollar. Doubtful that's going to happen, so in lieu of that, I'd still rather have BaD parts. It will be a sad day when they go away. At least they held the value to justify the price increase, IMO.