Dave's comments about working on Brian and Val's slideshow for their wedding got me thinking about the good number of them I've done over the years.
First off, my attitude towards these things is much like Danny's view of his musical skills: we're both into our respective passions as amateur pursuits, and we probably know more about our fields than the average person, but we're not good enough to make a living professionally doing so. So, if you want total technical razzle-dazzle and slick, polished results, go with a pro -- I won't be offended. =) Of course, if you want a personal touch... there's no substitute for having someone you know do it.
Having said that... here are some pet peeves of mine of various peoples' slideshows that I've seen (and I've certainly been guilty of some of them myself).
Computer vs. video playback: I've seen more than one slide show aborted due to technical difficulties, and invariably, they had used Powerpoint or even worse, an AVI file.
It's my very strong preference to use a video medium like tape or DVD to output the slide show to and play it back. With a laptop computer, there are just too many variables to consider, and too many things that can go wrong. With video, you just plug it in to the projector, select the video input, and there you are. No worrying about resolutions, screen savers to disable, long bootup times of computers, having the right AVI codec installed, etc. Just press play.
People who have no idea how to scan photos: uncropped white borders, no color correction (or even worse, bad color correction), 256-color dithering, improper aspect ratio... Yuck.
Posed shots: I love candid shots... maybe just my personal preference, but I like to see people doing other stuff than just posing. Baby pictures are an exception, because the cuteness factor compensates for it, but once you're past early childhood... argh!
Overused songs: Danny is absolutely right about "Lead of Love" being horribly overused in shows. And yes, his own slideshow featured it... at his suggestion, mind you. =)
I'm equally tired of Richard Marx's "At the Beginning" (from the Anastasia soundtrack) as well.
I'd also say that Kenny Loggin's "House at Pooh Corner" is well on its way to achieving the same status as the previous two. Of course, there's one particular person getting married this fall for whom that song is uniquely suited for... ;)
Using the standard fonts/animations/clip art that come with your software package: Maybe the average viewer doesn't know, but I can definitely tell if people are using the default stuff. Not so long ago, someone's "professional" wedding video went overboard with this, as if the producer wanted to include every built-in animated transition that his software package provided. A different transition for every scene. I wanted to puke.
Premiere's crappy zoom in feature: This is more of a beef with Premiere itself than with people, but I find it annoying that you cannot do any good zooming in using Premiere's built in stuff -- no matter how high resolution your source image is, Premiere downsamples it to your final output resolution, so even if you zoom in to a still picture, you can't recover the original detail, and you get horrible pixelation. Unfortunately, to get any sort of good zoom effect, you need to use another tool such as After Effects -- a real pain.
There are a lot of other technical gotchas, like interlacing, color gamuts, and other stuff, but I can forgive those if the people doing them aren't pros. But the things I mentioned aren't exactly rocket science either. I don't mean to be snobby, but sort like Danny/Henry ranting about how such-and-such song should be played in such-and-such key, I likewise felt like getting all of this off my back...