I'm sure it depends on the pubs and circles of people you know, but I don't find that any of my British girlfriends dress like sluts. I certainly see it on a night out, but don't feel out of place with not having everything on display.
I prefer to quality over quantity, so I usually stick to higher end (yet still affordable) brands like Ted Baker, Mango, and Reiss.
I agree with what a lot of the others have said, and this sort of says how I feel pretty succinctly. Except I can't really affod Ted Baker, but I do keep my eyes out for that stuff at the charity shops (yes, I do find it, too!)
I think if you are good at putting separates together you can create your own individual, non-slutty age-appropriate look. It's sorta what I do at work anyway on the mannequins in the window.
My own dilemma is that at a couple different points in my life (first about 10 years ago and second more recently) I just didn't know how to dress anymore. I think I started dressing too old and too boring. But both my old job and my present (dirty!) job don't cater to wearing anything you particularly like because it'll just get ruined. So I dress pretty boring at work, but I am trying to dress more interestingly, but more *me* when we go out.
This weekend we went to a 60th b-day party (hubby and I were the youngsters there!) and I did see a lot of mutton dressed as lamb, women dressed with "one foot in the grave", and women dressed too revealingly for their body type and age.
But I did see some who were dressed nicely and in their own style. Our one friend (she's 50-something) is sort of a cross between hippy and goth and even at her age it works great for her (flowy dresses and skirts, dyed hair, interesting jewellery). So you can piece together your own look if you really try, I guess.
I decided to have fun with my outfit and wore a black Next dress (empire waisted, sort of low-cut, but not grossly so, mid-thigh length), fishnets, a hot pink Monsoon fuzzy cropped cardigan, and my Converse high tops. I felt like me, and I felt comfy and not old or too young. By the way, everything except the fishnet tights I found at charity shops.