if you already have a basic and you're looking to upgrade, i'd suggest you save until you can do it all the way versus doing to what you can afford now and then thinking of upgrading again after another while.
go for a metal halide setup. 70W minimum to 175W maximum. i prefer to supplement with actinics but some people just do the mh with a higher kelvin rating instead (for the blue).
hellolights.com, championlighting.com, or marinedepot.com are all good (and affordable) lighting sources i've used.
if you retro, go for the 96W quad. the 55W/65W may be too long for your typical setup/canopy. good luck!