Yep, that one is always fun, love excel for that, if you use a sumifS it is the other way round, so I tend to just use sumifs even with one criteria as then don't have to fiddle with it if I want to add further criteria later on (also works for averageif).
Recovering from a sever case of manflu and can't for the life of me work out how to do this:
e.g. add all cells in B2:B100 where corresponding cell in E# = "fruit"
Sorry if that makes no sense!
EDIT:
What was trying to do is:
=sumif(F2:F200,"=cell#",D2:D200)
...but had the F and D cells the wrong way round :S