You should also pick a pump based on your head pressure and desired pipe size. For example, I have the filtration equipment located on the lower level of my house in a utility room so the total head pressure is roughly 20' by the time you factor all the elbows and actual height. For that I use a high rpm Dolphin 4800SP which is rated at 4800gph. It still flows about 4k at 20', whereas the lower rpm effiecient pumps are just trickling or off completely. The downside to the high RPM pumps is the noise and additional power consumption, but if you need it, its the only way to go. I can tell you that the Dolphin Amp Master series is about 10-20% more efficient than the sequence of the same flow rate, but its not a huge difference and I can't speak for the noise difference since I don't have a Sequence pump however based on comments above it sounds like they are quiet and may be well worth the additional power consumption.
Depending on your setup you may want to run dual pumps for higher redundancy and therefore get 2 smaller pumps so if either dies on you your fish will be fine for quite a while. I had this setup on a prior tank and worked great.
Tell us a bit more about your planned setup. Either way good luck to you, with a 5k gph pump you are probably planning a very nice tank! :happyfish