Go for Fischer/Lotto. THey give out sponsorships like crazy to ne1 that is pretti much ranked in Aus. But personally id try and get Diadora or sumthin, coz if u get Lotto u hav to use Fischer racquets, and it not worth changing racquets just for sum ...
Yonex definitely makes the best badminton racquets! One of the best is the Yonex Armortec 900
The best racquet from Yonex, IMO, is the Muscle Power 100. It is balanced and allows the player to smash really really hard. Also, the control and feel for it is really good since it's balanced with a little head heavy-ness.