Mafia Wars question...? (When should I cap energy?)?

I play on Facebook. I am a Level 51 Maniac. I am just wondering when I should stop putting points into my energy stat?

I know some friends that have like 1500 energy, and it just seems like a big waste to me. Sure they might be able to do more jobs quicker, but in the long run isn't that 1500 more points I could have put into defense/attack? Here are my stats so far:

Energy: 283 (Planning on stopping at 300...)
Health: 120
Attack: 50
Defense: 25 (Plan on raising after capping energy...)
Stamina: 10

Any advice guys, or your stats? Any help is appreciated! I will give out a best answer.