I use 10's, 11's or 12's for piecing, depending upon the size of the thread.
I use Organ Brand mostly - I can buy them on eBay for as little as $12 per 100 and they're really nice needles.
I recently bought Orange Brand to try them out - again, about $12 per 100 and they supposedly use German engineering and quality control in the manufacture, so I think they're going to be fine.
I've never had any problem at all with the Organ brand, but I do change the needle quite frequently no matter which brand I'm using or what machine I'm sewing with. When embroidering or FMQ, I only put about four hours on each needle and I change it before any problems start showing up. For regular sewing and piecing, I usually change the needle after six or eight hours.
I also like Klasse' and Schmetz brands - they cost a lot more, but they make a lot of specialty styles.