The Fein Multimaster. During our recent three year restoration I used mine nearly every day (and sometimes all day). It did jobs that there was literally no other way I could have done. The adjustable speed and ultra precision German engineering make it the tool of choice for people who use one on a daily basis. I've left it out in the rain, dropped it off the deck to the ground, and still it hums along like new. A tool rep told me they use these in the Ferrari plant in Italy and the tool is passed from one shift to another running nearly continuous and goes for up to two years without maint. This would be a lifetime for the average professional user. For occasional use any of the others will suffice - I have a friend who bought a Harbor Freight model which he uses about once a month, and loves it - he gets as good results as I do and the cutting blades are like five bucks a pop (of course they don't last long - but neither do his projects )

I had a very hard time letting go the money to buy this tool, but now consider it the best money I have ever spent on any tool. The Fein accessories are slowly coming down in price which will be a relief.