Hmmm all depends of course on personal choice really, and what is actually available at reasonable cost in your area!.
As a general guide, you can expect anything carrying the NJD or Abstract Logo to be reliable lighting effect.
Consider a combination of at least two DMX moonflowers (NJD Datamoon / Abstract Galactic Star / Abstract Twister 4) and two or four DMX Scanners (NJD Predator / Abstract Moonscan / moonray)
The above mentioned NJD Datamoon is old hat to some, but it is frighteningly reliable, virtually bombproof and has a lamp life extender which saves a fortune in lamps

. I've had two MK1 datamoons for the last 5 years, and also two MK2's for 3 years...non of them have every had more than a lamp failure!. If your on a budget consider the NJD Chaos 2002...a newer, non DMX version of the Datamoon.
Chances are the hirer has replaced the lamps with lower wattage has you have mentioned, or maybe they just need the optics cleaning! - another thing to remember when you have your own lighting...Lighting Optics hate Hot Dusty conditions, Smoke Fluid Residue and vibration. So make sure your effects' mirrors, gobos and optics are carefully cleaned every 6 months. Mke sure fans are working and not clogged with dust, and that the lamp fitting is securely pushed against the lamp!.
Also, if you can purchase one locally, consider a Green Laser!, These are a stunning addition to any lightshow and far brighter than most lighting effects.