Light strings(9's or 10's) work just fine in standard tuning(not that they don't sound good in dropped tunings).Thick strings serve a better role if your always tuned down to C or something where the slack allows the string to move and feel about as loose as light strings at standard tuning.

Your pickups play a role in how thick or thin/shrill the sound is.Your neck pickup will give a warm thick sound where the bridges will give a treble/midrange sound(and works better to produce crunch when using distortion).I personally like using my necks pickup for lead since it gives an almost keyboards/piano like tone.The setback is that natural and artificial harmonics won't jump out as easily...anyway,point being,your pickups do matter as does the rest of you rig.Thicker string will give you a thicker sound..light gauge will be more bright.