I really disagree about black. If you think black looks cheap, you're buying the wrong suits.
The fabric is very important if you want the suit to last and clean well. I go for pure wool or mixed fabrics with a very high percentage of wool.
D&G do very very good trouser suits which are lovely. Gerad Darel is worth a look.
Paddy Campbell is fabulous-black and navy wool crepe, with dresses, jackets, skirts and trousers in the same fabric so you can mix and match and use items from different seasons. Highly recommended. I've got a dress and coat suit from there which is years old but doesn't look it and always gets compliments.
Vivienne Westwood suits are very nice, especially if you are an hourglass shape.
In the US Jones New York is good and Neiman Marcus has a good selection usually.
Try Yoox.com too, especially for separates. There are some good but not well known Italian brands on there like Incotex who do really nice tailored trousers and skirts.
I love suit shopping, it's casual I have trouble with.