I've used both open and closed style.. both work, and used the ones from monoprice. the only complaint I've had with them so far has been if you take them in and out a lot, they lose some of their grip
Here is a line of bananas from GLS Audio. I particularly like their locking bananas compared to the rest of their line and they nicely accept 10awg Belden speaker wire and probably even 8awg speaker wire as well.
I got the locking GLS Audio plugs. I would not waste your money on expensive plugs as it does not really change or help the sound. I don't hate or love the locking plugs, I could leave with or without them. I liked the look of the ones I have.
If you plan on leaving your system plugged in for the next few years get locking ones. Other wise the regular ones are way better for quick swaps.
I have the locking banana plugs on Accusound interconnects. They work fine but just one word of caution do not over tighten. I did it once when I first installed them and had a devil of a time getting them loose. With moderate pressure they are fine. :T