* The actual % that is applied towards finding each type of item. Magical is full, Rare/Set/Uniques are less.
How much you want to wear should be based largely on these percentages. More always helps for magical items, so if you have 1000% MF you'll get incredible amounts of blue items. The weapons might be useful, but the odds aren't good. Charms and Jewels are not boosted by your +MF%, so this doesn't help with those. Best way to find more of those is to kill more things. Rares increase pretty well up to 600% MF or so, but Set items really slow down past 400 or 500%. Uniques are much the same, but even worse in the diminishing returns. Notice that from 300% to 1500% only increases your Uniques MF% by 101%.
If you can get to 250-350% that's really all you need, in terms of finding Sets and Uniques at an increased rate. More after that generally doesn't make enough of a difference to be worth the equipment sacrifices, especially if you are playing Hardcore.