This is actually a moveset I find to be best overall:
Leech Seed
Substitute
Energy Ball
Focus Blast
Being the fastest sub-seeder back in Gen4 (now Jaroda has that honor however) make use of this. Energy Ball is obviously for STAb and Focus Blast has great type coverage. If you are good at Hidden Power, a Rock HP might work well. I just hate Hidden Power though. If you think you must keep Dragon Pulse (I wouldn't) I guess you could keep it over Focus Blast (but don't, Focus Blast would be better.)
Edit: Okay, if you don't want to sub-seed, go with:
Focus Blast, Energy Ball, Dragon Pulse, Synthesis/Hidden Power Rock