Flyboy:
Yeah, you should definitely get a bass trap in that corner behind the speaker on the right side, and probably in a few other spots too. You really need more than one bass trap in a room for them to work properly I think. At least that's my understanding.
I highly recommend contacting Realtraps. I bought a set for myself, and I found that their traps work REALLY well. They also look great (much better for the WAF than some of the other offerings on the market), and those guys are SUPER helpful!
I've read Ethan Winer's posts over the years on forums, and he's always been very knowledgeable and really helpful to people. I actualy ended up dealing with Scott Veenstra there when I contacted them. Scott really spent a lot of time with me, and was very patient in explaining how the acoustics work and in helping me find the best setup for my room, to get the best performance for my budget and the number of traps I figured I could fit into our decorating scheme. Way above and beyond the call of duty, actually. He even came up with some ideas to make some of the traps less noticeable, which made my wife really happy.
Scott also took the time to help me sort out some other issues with my speaker and subwoofer placement. I have to say the just the extra help alone that I got from those guys was well worth the money spent, and my room sounds terrific now!