Wireless...
Well, I don't know from the best, but I use the Samson Airline Wireless systems for four reasons:
First, they sound good. I've done extensive A/B'ing with the wireless and wired systems, using my Peavey MidiPro in my rack and my Whirlwind Selector with my combos so I can do one button aural comparisons. Yes, there is a difference, but it's very subtle - and I wire EVERYTHING with George L's in my rack and combo settings (which is to say, I'm pretty tone-anal). Granted, you have to spend some time setting up your levels on the wireless to suit your rig, so it's not quite as plug'n'play as a good cable, but I mark my settings on the system so they're easy to find again if I lose them... Anyway, I wouldn't record with the wireless, but it's fine for live use.
Second, the form factor. I've had belt-pack wireless systems and they are such a pain in the butt - literally if you break the belt-clip on the thing and have to stuff it into the back pocket of your jeans... The Airlines tiny transmitter is great - it stays well out of the way, and eliminates the wires COMPLETELY!
Third, the price. You can - no doubt - buy a better wireless system for more money. Probably significantly more money. But wireless systems essentially replace a $20 wire, so how much are you willing to invest in them? I've heard it said that anything under a thousand dollars isn't a good wireless.
I'm glad I'm not in that camp - the Airline is good enough for me.
Lastly, safety. Just like everyone else here, I've played in places with questionable wiring quality, and zapped myself by touching my lips to a mic while holding my guitar. The last time that happened the shock knocked about three feet through the air and left me sitting on my ass looking at the pretty birdies for a couple minutes...
I figure that the price of a wireless system of any kind is cheap insurance against a potentially fatal electric shock. I always use a wireless system when playing out, now - and it gives me peace of mind, if nothing else...
