I posted this before, and it's always the same.
Here's an idea. Look for them yourself, find the ones that work for yourself, and make them "good"! In all honestly, looking for the shortcut by asking for "best of" effects isn't gonna do you any favours, and 95% of the time will not get you the most hard-hitting effects you can perform. That's right, asking for good tricks will actually, the majority of the time, get you tricks that, when performed by you, will be second rate and extremely common. So you'll be performing the same old stuff and probably not as well as you could be.
Rather than ask "Where can I find the best effect", ask "Where can I find effects (possibly of x plot or from x magician)", go out, look through everything, and find what works for you. You want average material, ask for "good" DVDs. And if you're satisfied with decent, go ahead. You want the best material, which has the highest possible impact? You'll have to work harder than that.
The main reason for this is that the strongest effect in my arsenal, in all honestly, would probably not work at all for you. This is due to many reasons - personality, presentation, and just the effect in general. Many, many people for example list Stigmata as their strongest effect, and many people buy it. You wanna know the truth, 95% of people's presentation of Stigmata is ****. Stigmata could be so, so much more.
If you really want strong effects, you need to tell us what you're interested in, specifically, a plot or an author. Then you need to go look at everything by that author or on that plot, and decide what works for you, use that knowledge to mix the effects together, and base a presentation on what appeals to you, not what appeals to us. My favourite effect happens to be Zamiel's Rose, and yet I barely know anyone who has the personality to pull it off, so I never suggest it, it would be a travesty, the epitome of ruining magic.
Go buy a book or something, that's where the good stuff is.