I personally was not impressed with those foam inserts that Bell sells that the OP linked too. I tried them out for a week and then took them off and put them on a spare loner bike so they wouldn't go completely to waste. I am, however, a big guy who carries loaded panniers and/or back-pack on almost every commuting ride.

I am personally running Bontrager Hard Case Plus puncture resistant hybrid tires (available locally for cheap and the puncture protection is in the sidewalls not just the bottom of the thread) PLUS Mr. Tuffy wide brown color tire liners PLUS thick heavy "thorn buster" type tubes PLUS 4oz. of that green goo self sealant stuff injected inside the tube upon removing the valve core before airing them up initially PLUS nice heavy thick rim liners that are triple layer construction with the two outer layers being soft thin rubber material and the inner core layer being tough Nylon tight weave fabric.

Flats are all but non-existent for me now and the last one I had quite a while ago was a valve stem failure. Yes, the ride is noticeably a little stiffer and I added a couple pounds of weight or so to the bike but it is well worth it for me since I encounter broken glass and sharp metal debris on a daily basis not to mention some killer pot holes and sometimes to maintain my safety in traffic I have no choice but to ride right through it since swerving to dodge could endanger me. Bear in mind that I'm running 26" mountain bike type heavy duty double wall 36 spoke front and 48 spoke rear rims with hybrid commuter tires and not narrow road tires on lighter built wheels simply because the terrain over which I commute by bike is simply to rough in too many places for anything less to be reliable. Yes, I have an old but light weight ten speed road bike with narrow little 27 tires on light duty wheels with just regular light weight tires and tubes that I take on a pleasure cruise every once in a while on a pre-scouted route that I know is safe but that is as far as it goes for the roads up here.

One other possibility I might note is that when I was a kid my brother had a bike when he was a teenager that we picked up a yard-sale that used the largest size of solid rubber wheel chair tires that were completely solid rubber through and through. That bike was a fast ride on smooth pavement and was obviously no worries about getting any flats. Not sure how one would go about exploring that option and it would probably a custom proposition but there is a thought in there for someone that is willing to explore that option.