I have found that I prefer the individual adapters versus the multi-task ones. They can be found quite cheap (as a bundle similar to the above linked one, but much less) if you shop around. I usually know where I am going and can pack just the adapter or 2 I need, and it works better than a bulky unit (less space, less weight, less complex).

here is an example. http://www.amazon.com/gp/product/B00013BL18

There is also a set out there that has grounding plugs for all the types (this is a set I have). I think it was only about $15. (They look similar to this one: http://www.amazon.com/PLUG-ADAPTER-C...sxp_grid_i_0_1 )

However, some people might travel from one country to another and find the multi-adapters the better choice.