In reply to CJD:
I'd never had an SLR before, although I had used my Dad's old Minolta a little. My preconception for getting into this game was to take more climbing pictures, but in the last year I've taken very few! Instead, most of my shots have been landscapes/candid portraits. I quickly discovered that the kit lens was limiting and invested in a wide-angle/fast prime. I also made a snap purchase after finding a bargain on an old telephoto.
In hindsight, I could have saved some cash by skipping the kit lens - which sees very little use. However, when I first bought the camera, I didn't expect to buy more lenses anyway!
As a more experienced photographer, you know your style and whether a lens choice will limit your creativity. Aside from the low-light pics, do you ever find a mid-zoom a problem? If not, then there's little reason to buy more lenses. You had a fixed prime (50mm?) on the Yashica, right? Maybe a mid-zoom already feels more flexible than this?
For me, the gear is only a means to an end. Having said that, the prime is my most common choice at the moment (compact, wide aperture, just zoom with your feet!), but it's not right for everything. As my tastes develop, I could see how I might add to this collection, but I don't feel the need for "pro" zooms or more than 3-4 lenses. It's also worth considering that the high resale value, longevity and competitive online pricing, make lens shopping more affordable/attractive.
Go on, remortgage and get yourself all that kit you're lusting after!
J