I recently posted a video to my youtube channel talking up the positives of the trap bar deadlift and personally I think it has quite a lot more benefits in terms of training for jump performance than the regular straight bar version (easier on the lower back, easier to perform correctly, lift more weight, more quad involvement). If you are already happily squatting though then there will be some redundancy in doing both that and a TB deadlift.
As Damien said earlier - pick one, get really strong at it and do plenty of jumping.