I just finished my keggle builds earlier this year. I put two 1/2" couplings in. One at the bottom for draining and one at the top for recirculating. I also added a sight glass and thermometer while the welder had it all. I got most everything from Bobby M, it was all great! I use the cam lock disconnects. I haven't had any problem with them, although I think the standard connects that are like the ones on an air compressor would be easier to take on and off. Like I said, I'm not complaining about them, they might just take .5 seconds longer.
Anyways, what are you using it for? Boil kettle, mash tun? I'm assuming boil kettle. I have a false bottom on mine, it seems to be kind of handy. It generally stops most of my pellet hop sediment. I got it from Midwest. Is actually shaped for a sanke keg, so it fits nicely, and fairly priced.
If you have some basic soldering skills (REALLY basic), I'd save some money and make your dip tube yourself. It took me like 6 minutes to make all of mine and they work great. Here are some pics of my stuff I did. I haven't routed the recirculating/whirlpool pipe yet, but it will basically direct the output along the wall of the kettle. I've just been too busy loving my system to want to do more work!