For as long as I've had a dSLR I've always wished I had a Macro lens. In fact, specifically, I really want the Tamron 90mm Macro lens. Funny thing is, as lenses go, it's not even that expensive so I'm not totally sure why I don't already have one.
I suppose it probably comes down to the fact that it's not a lens that I've ever really "needed" ... it's always been much more of a want. I've heard that in addition to macro use, the Tamron also works really well as a portrait lens. But between my Canon baby L 70-200, and a sharp Tamron 28-75, I think got portrait range pretty well covered.
Over the years, I've actually had relatively good luck shooting macro type scenes using a long zoom lens, such as my Sigma 50-500 "Bigma". But obviously it's not ideal. I want to be able to get right up there next to the bugs. ;-)
Here are a couple of shots I took today with my Canon 70-200 F4L. They're not bad, but don't quite have the level of detail I expect I'd be able to get with a real macro lens.
I don't think any new lenses are in my Christmas budget ... with 7 kids to buy for, there's rarely much left over for dad. But who knows, if I have a good spring, maybe by my birthday in March that 90mm will be in the cards.
Keep havin FuN!