OK, here's something I do actually know something about.
LEDs will, in fact, put out
more useable than a traditional halogen fixture if wattages are equal. The beauty of LED is that most of the input energy goes to the light, not heat. An incandescent is 2% efficient - 98% of your power goes to heat. A halogen is about 4% efficient. LEDs, on the other hand, are up to 80% efficient.
What does this mean? It means that, yes, a single 3mm diode will not match a 6 Watt fluorescent, let alone a 40W filament bulb. However, you cluster a bunch of 10mm diodes together and they will match, if not outright beat, any similar fixture with the equivalent power consumption.
Additionally, in most cases - including our use here for band lighting, as well as my area of more interest in salt water aquariums - lumens aren't really what you should be concerned with. LEDs have a much tighter focus than halogen bulbs, so the "throw" on LEDs is far better.
The other thing is that you *can* in fact run a boatload of LED fixtures on the same circuit as your PA gear. It's not recommended, but sometimes it's unavoidable.
A Par 64 can loaded with a 400W bulb is matched visually in a stage setting by a Par 64 with 183 10mm diodes - pulling 30W.
After seeing many, many setups and buying and experimenting with lots of different ones, I went with two ColorStrips for my wash lighting. I wish I had taken pictures at the wedding I did last night, but I was quite busy with the crowd the entire time. The reception hall was about 50'x70', and I was setup directly in the center of the 70' wall. The ColorStrips would light up the entire room in a wash - I had them pointed straight ahead at the other wall, approximately 15' up. They're using 384 5mm LEDs each.
With the exception of the DMX controllers, LEDs are so incredibly simple. They're solid, so you're not going to break them. They last for thousands... possibly tens of thousands of hours. If anything really goes wrong, it's usually the power supply or a shitty soldering job. Everything comes from China nowadays - when it comes to LEDs there's no compelling reason to go with an expensive unit over a cheap one. An expensive one has just as much statistical possibility to break down during a gig as the cheapies. The bonus with the cheapies is that you'll probably be less afraid to crack it open and fix it yourself.
To show you how simple, I present to you this from DJF:
$10 homemade LED par cans
OK, onto your setup. I would indeed go with two trees, but you're going to need a DMX splitter for convenience. Chauvet DMX-2x or Data Stream 4 will allow you to split your DMX signal - I'd go with the DS4.
Build yourself some bases for the Par 38s, and use those as uplights. Two uplights behind the drum kit, and two uplighting your mains (or just clamped to one of the legs of the speaker stand). If your mains aren't on stage with you, I'd do 4 uplights behind the band. Run DMX from two channels, if necessary.
The grab two ColorStrip ($178 each) and center mount the scanners on each tree. Run DMX to each tree.
That puts you right around your $500 budget with some pretty cheap trees. Later on, if you want a dope EFX unit, grab a Martin EFX series, at least the 600 if not the Wizard.
Edit: I do agree with JC on a couple areas:
1. Yes, the fading is better on more expensive fixtures. Not enough better to warrant the incredible price jump, IMO.
2. RGBAW is definitely better, but most colors are possible with color mixing even on the cheap fixtures. I don't really notice any bleeding effects on my cheapo Chinese ones. Pic below is red+blue mixed at 100%, resulting in a pink/purple.
3. LEDs are not ready to replace everything yet. We're still a couple years off from great scanners, yokes, and effects. Unless dots are your thing.
