Multi-cannon and cannon ammo is cheap; if you were running cannons, you'd have made far more from the bounties than it would have cost to buy ammunition - you're talking about cr200 for a Sidewinder (bounty cr1-3K) up to cr2-3K for an Anaconda (bounty cr60-140K). Power management becomes a hell of a lot less stressful. Once the shields are down, pips to SYS and ENG (and 0.5 pips to WEP) and blow holes in the hull.
The maths don't lie.
Additionally, gimballed lasers suck - 25% less damage and they're largely ineffective over 1.5KM. I'd suggest:
2 x fixed beam lasers
2 x gimballed multicannon
You can choose which you want on the medium hardpoints and which you want on the small hardpoints. Personally, I use beams on the medium points and gimballed cannon (not multi-cannon) on the small. It makes light work of shields on most ships, and the DPS of the cannon makes up for its light weight and slow fire rate.
I'd only go for all energy weapons if I were exploring and knew I wouldn't be seeing any stations for a while.