Other than Uline, I buy at all these.

FWIW, B&H has a lot of tech stuff not just audio/video; I'll typically check there before amazon - just because I like dealing with B&H.

Speaking of video, if you're looking for broadcast studio quality production gear, check out markertek.com.

For networking gear at reasonable prices, it's monoprice.com. I've wired a couple of commercial office suites with their gear. For instance, their plenum-rated CAT6 is every bit as good as Belden - at about a fifth the price. Need patch cables in bulk or patch panels? That's totally where.

For antennas and wireless / radio gear, it's Fleeman. Anderson & Bird (fab-corp.com). Building your own WISP? Need panel antennas or parabolics or repeaters. This is the place.

Agreed that digikey has an absurdly out of date web site. I think it might be a point of pride, well, and the printed catalog that weighs a couple of pounds.