Determining how to arm you predator for any specific list depends on the roll you want it to fill. Currently the power list involves the "dakka dakka" predator which has the autocannon, heavy bolter sponsons, and storm bolter. This is a lot of anti light infantry firepower for under 100 points. The next configuration is the generalist shown above. It has the TL lascannon for anti tank duty and and HB sponsons for anti infantry. This is a predator for use on the move since often only 1 weapon is brought to bear on a target so I add the dozerblade. This one is a significant point jump at over 130 but can help when you need a little overall boost to your firepower.
Another option is the autocannons with the lascannon sponsons. This is cheaper than the previous one but is for anti tank duty not general support. It is able to engage light and heavy armor. When you are on the move you will have to pick between the autocannon and lascannon. If you are firing at Armor 10 the autocannon is best. At armor 11 they both generate the same penetrating hits but the autocannon generates twice the glances so use the autocannon. For Armor 12 or above the lascannon is best. This tank might come in handy against squadrons of light vehicles like walkers or skimmers.
The final option is the all lascannon predator for anti heavy armor. This one rings in at over 160 points so is not a popular choice. I would probably only bring this for anti monolith duty where melta's are not effective or for opponents spamming nasties inside Landraiders where the stand off weapon range is important. This tank will generate .75 glances + .75 penetrates while stationary against AV 14 not to shappy. This compares to a single multimelta at close range with .1 glances and .4 penetrates assuming 2d6 armor penetration.