The number of electrical outlets you need will be determined on how many appliances you plan on using, both now and in the future. Since your plan is to heat the room, you will still need outlets for lighting, the air pump, potential heaters, potential power/canister filters, dehumidifier, etc. Definitely figure out the tanks/racks position to avoid blocking any outlets to easy access.
For our 10 ft x 12 ft fish room, we installed 2 outlets on the short wall, 3 outlets each on the long walls and 1 outlet for the air pump and they are on 4 separate 20A circuits. We are using 4 foot long workshop style 10 outlet surge protector strips per rack. This allows us to hook up heaters, lights/timers and the occasional power/canister filter for extra filtration. The electrical outlets are at normal floor height, in the wall, to avoid issues down the road when selling the house. The strip outlets are mounted on the wall above the second tier of tanks within easy reach. This has worked well for our purposes.
How are you planning on heating the room? If electric, you will need a dedicated circuit for that also.
Is your plan to drill the tanks for water changes?
I also need to setup the room for use as a bedroom afterwards so I need to install outlets at a normal height as well I will be putting 1 in the small section which will be running the air pump and the dehumidifier on 1 breaker and 3 outlets in the other room on another breaker for individual lighting if needed I plan on setting up a planted tank which I have the flu Val led light for plants X2 and some lighting once stands and tanks are set up then the general lighting for the rooms will be on another breaker and the electric base board is on another breaker so I think power should be distributed well
As far as heating the electric base board and the dehumidifier will be doing the tanks ambient style
As for the plan for the room it is hard to say I have like 9 spare tanks ranging from 5-90 gallons which I will be starting with but plan on slowly aquire in more permanent set up I plan on doing a rack of 15-20 10gs about 10 20th
And I have 3 40g breeders as well I plan on building a sort of pond in the nook under the stairs approx 6ft by 3.5 and 2 feet high but only as I can afford things I just want to set the room up right so I can build accordingly