I wholeheartedly recommend the 50mm prime lens for most things, especially low light. Wide angle for landscapes and some urban photography (I have 12-24mm).  

My beautiful 105mm vibration reduction macro was another very good buy and I use it for a lot of things, mostly macro closeups, abstract and portrait and also in place of a zoom lens for distance shots but it is far less flexible in that context.

I acquired a second hand sigma zoom lens 70-300mm which surprisingly I make little use of, mostly because I need a tripod or support to prevent camera shake.  I am more likely to use the standard kit lens - 18-70mm.
I also have a fisheye and a lensbaby which are novelties that I should have retained more self control over.

I desperately want a tilt and shift lens for architectural/urban photography and some lens extenders to do ultra close up macro work. those will be on my wish list for some time I suspect.

Ad astra per aspera