Seating is always very subjective. For me:

1. I like to be able to exit the aircraft quickly - so the forward cabin is preferred.

2. I don't like to climb over people, so aisle is preferred (which also helps 1. above).

While bulkhead seats (row 31 - first row in economy for Thai) don't have anyone in front to recline into your 'space', you don't have any storage space under the seat in front and so items must be stored in overhead lockers, slowing exit (provided you have small carry-on bag). Also, the seats are slightly narrower to accommodate the tray-table (stored between seats). Armrests cannot be raised.

So, on A300, I prefer row seats 32 B/D/G/J. But I'm flexible !!

Seatmap here:
http://www.thaiair.com/Travel_Destin...ps/A36R1_l.htm

Pictures here:
http://www.airliners.net/open.file/0856379/M/
http://www.airliners.net/open.file/0589086/M/
http://www.airliners.net/open.file/0630534/M/

Enjoy!

TK