I have had two in my kitchen at times. Since I teach the Wilton Classes and have to make icing once a month at the store, I carry the stand mixer so I have my hands free while showing everything. I have the big 6 quart which I love at home, but hate carrying it since it is so big. Plus I don't think it mixes small batches of things super well. So for the classes I borrow my mom's 4.5q and carry that to class. After class it will end up at my house next to the big one sometimes for a few months.
There are times when they are nice, and there are times when it jsut takes up cabinet space. If I had extra money I would probalby buy a 4.5q or 5q of my own and keep the 6q was well. That way my mom could have her mixer back (not that she uses it super often.)
If you don't have the money for buying another mixer or just aren't sure you want to spend that much, how about looking into a second bowl/beater for your mixer? I don't know about the brand you have but KA does sell extra bowls and beaters. That will allow you to do both things with out having to wash in between.
I also have a hand mixer (KA) that I love as well. I use it for mixing my cake batters, so I don't have to wash the stand mixer bowl to make icing.