I've been timing textures on three different systems. Pardon if I use OSgrid as a benchmark:
On OSgrid, the smaller a texture is, the faster it loads. So a 128x128 texture will load very quickly, a 128x256 will load in 2-3 seconds, 512 will load in 5-7 seconds, 1024 about 8-10 seconds. (Note these are generalized averages and will not apply to every single texture load ever. Figured I better cover my rump there.) ;D
On Kitely, the average texture loading time (on my system, and it's a moderately-fast system) is 15-17 seconds. Today I was testing 128x256 textures and they were taking an equal amount of time. This would be considered exceptionally slow, especially for such small textures.
It's possible this is partly a matter of how the viewer is interacting with the asset server and suspect that some tweaking on both ends is probably needed. But as a creator I'd love to see that 15-17 seconds drop at least by half, and smaller textures load faster. When one is going through textures to find "just that right wood floor"... waiting 15-17 seconds for a texture to rez can be very time consuming. What I usually do is call up half a dozen textures at once hoping they'll rez faster overall and then look at all of them at once, but that seems to extend the load time overall. (I've never gotten used to using a texture organizer; they've always felt cumbersome to me.)
Please note I haven't done extensive testing on this yet, using multiple viewers, nor have I formed a consistent average of statistics to back up this post. I'm just pointing out slow texture load times from a user's viewpoint and timing a couple dozen textures to see the average overall: it's slow. Would like for someone smarter than me to figure out why, and fix it.

Thank you thank you!