mf?

[Blue]

Remember that while a lot of mf is good, this also increases your chances to get magic by a lot more.
For example (this isn't real numbers, just an example)

350% MF gets you
350% more chance to get magic (blue) items
100% more chance to get rare (yellow) items
40% more chance to get unique (gold) items
0% more chance to get runes

So you have to take the good with the bad.
I can't tell you what a good mf is at, but I wouldn't alter you basic char to get more. For example, you could trade that ptopaz for an um if it helps you more. Or even trade the ist up for a facet.