I recently built a 10" ported HT sub for a house warming gift. It had a 180W plate amp and was tuned to 23Hz. The driver used was a Dayton MKII from Parts Express.
I have a chip amp right next to me that I'm building based on Brian's gainclone cards from www.diyaudio.com
This project has been on th eback burner for months. I should really finish it
My next couple projects involve Silver Flute Speakers.
And perhaps a servo controlled sub from www.rythmikaudio.com
Of course my Suburban has been sucking away at my bank account as of late due to old shocks, and some transmission upgrades I must do so that I can tow some stuff.