My favorite pants are the Groove Pant and the Sequence Crop. They have a wide, smooth waistband that isn't too high, or too low, they're quick drying and super comfy. As an added bonus, some pairs are reversible (reverse to all black and the logo is on the leg). Another plus is that Lulu will alter pants for free! That is a BIG bonus for my short legs! :) They come in all sorts of colors too - most of which are seasonal - so not everyone at the gym will be dressed the same.
I also love my Shape Up jacket. Its stretchy, moisture-wicking and has zippered pockets.
My most recent (less bank-breaking) purchase was a headband. Its so hard to find ones that are cute and stay put, but these double bands to the trick.
Next on my wish list are the Stretch Pant, Om Jacket, the Dance Studio Jacket and the Reverse Lulu Hoodie.