There's a pretty wide range in regards to recommended turnover. I know there are guys on here that think 10+ times an hour is necessary, but my tank turns over around twice per hour and I am very happy with water quality and clarity. Electricity is expensive where I live, so if I can get the water quality (no Ammonia or Nitrites) and the clarity I want with a smaller pump then I'm happy because of the money I'm saving on my utility bill.
Tips:
1. Make sure you have large drains. You can always reduce a drain or valve it back, but you can't easily enlarge one. if your drains are too small, you might not be able to run the size pump you'd like. I would go with two 2" drains (minimum) on a tank that size.
2. In regards to your return pump, I have found that Laguna Max Flo pumps move the most water per watt of eletricity consumed of any pump on the market.
3. I would go with the largest sump you can fit under your stand. The smallest I would use is a 100G.
4. You might want to look into bead filters and forget about running a sump all-together. Their backwash feature seems to make maintanence a breeze, as opposed to having to clean filter socks. I've never used one, but cleaning filter socks is getting pretty old.
Check out the link below to see the filtration on my 770G.
