I've got the EFs 15-85 on my 7D, and I love it. An alternative to that one will be the EFs 17-55, on a crop-body it's more useful than the 24-70L (unless you really really need the 55-70 range in f/2.8).
First thing to do is play around with the lenses you have, try out the focal lengths. Do you need wider angle than the 28mm you have?
If you need wider than 28mm, is it for indoors, or outdoor landscape? if indoors, the 17-55/2.8 will be the go. If outdoors, go the 15-85.
If you really really don't want to buy EFs lenses (because you're going to upgrade to FF tomorrow), the 16-35L could be a good bet in that range and keep the 28-135 (or go the 24-70, 24-105).
(Still, even if you are going to go to FF very soon, don't discount the EFs 15-85 and 17-55, they both hold their value almost as well as L lenses do, you could sell them if/when you sell the 7D and go FF).
If you want a low-light prime for indoors, the 35/1.4L is a good choice because it frames like a 'normal' lens on a crop body. If you can deal with Manual Focussing, get the Samyang 35/1.4 and save 70% from the canon L for the same IQ in the centre, and better on the edges.
As for the long end, do you intend to do indoor portraits? You can try out the focal lengths on your zoom to see if you need anything in the 50/85mm range. The 50/1.8, 50/1.4, 85/1.8 are all great for their prices. Or if you'd rather stay with the zooms, and if you need low-light indoors longer than 55mm, that leans towards the 24-70L
(and if you want long-range outdoors for wildlife, that's a different question again, the 70-200 f/4L is great for the price. But if 135mm is long enough, then just keep with the 28-135 for now. My 15-85 is a good outdoor-hiking lens, great for lanscapes, and can get good photos at 85mm if a big animal wanders past. But i'm obsessed with birds so my 70-300L is almost glued on my body these days).
to sum up, my recommendations:
EFs 15-85 for outdoors general purpose zoom.
EFs 17-55 for indoors general purpose zoom.
24-70L only if you need the 55-70mm range in f/2.8, and don't need wider than 24mm. (or couple with the EFs 10-22 or 16-35L, or any number of 3rd-party ultrawides)
24-105L if you need extra length, and don't need wider than 24mm. (or couple with the EFs 10-22 or 16-35L, or any number of 3rd-party ultrawides)
16-35L only if you are going FF very soon.
35 f/1.4L if you can afford it.
Samyang 35 f/1.4 if you can't afford the canonL and/or don't mind Manual Focus.
50/1.4 or 50/1.8 or 85/1.8 for indoor/lowlight/portraits, check what length is good using your zoom.