Talking about anchors with boaters is like talking religion.
Lots of factors that you should consider when it comes to anchors:
1. How strong/young/old are you? Pulling an anchor up by hand from 60' down (about 150' of rode to pull up) a couple times while fishing will quickly wear you out. When I go out fishing, I'll drop the anchor as many as 10 times during the day. My 62 year old shoulders and arms don't appreciate that kind of wear and tear.
2. What kind of waters (big waves, little waves, windy, calm) will you be boating in? A pontoon boat is going to automatically take any wind and make your boat a sailboat. Adding waves, currents, etc. are only going to make it worse.
3. What kind of boating are you doing? Will you be fishing (where you might pull the anchor 10 times while out), or will you mostly be just "setting it and forgetting it" for the day while enjoying your favorite adult beverages? This ties closely into #1. If you're doing it often, I'd consider the lightest weight anchor that you can get that will hold you.
4. Will you be anchoring out overnight, or just day trips? If you're doing this, you're going to want an anchor that sticks like glue or else you'll be up all night worrying if you're dragging the anchor.
5. Would you consider a windlass for pulling/dropping the anchor. This will allow you to use pretty much any anchor.
When I went through this checklist, #1-4 led me to buy a
Fortress FX-11 anchor. it's a Danforth style anchor, but holds much better than any other Danforth I've had - and MUCH lighter in weight. You can adjust it for mud bottoms or sand bottoms, based on the angle of the fluke (32º or 45º). I could have gotten away with the FX-7 (weighs 4 lbs) but because I'm out in the Gulf I wanted a little more holding power (FX-11 only weighs 7 lbs). Here it's all sand, so when it sticks, it STICKS. I've rarely had it slip on me, and when it did it was my fault for being too lazy to set it properly. The think I liked about the Fortress anchors are that they're so light.
A windlass is a great addition if you're doing a lot of anchoring, but in the end, you still need a lot of rode and a good amount of chain. I have 8' of chain on mine (which by most standards is short for the type of boating I'm doing). You'll want at least 150' of rode for the depth of your lake to give you a 3:1 ratio at it's deepest point.