I know of many packs that can easily hold all that. No hydration packs, though. Does your bike have water bottle cage mounts? If so, a pair of cages and bottles should only cost about sixteen bucks and possibly negate your need for the hydration system.

After a broken knee and a year off the bike, getting back into commuting I just grabbed a cheap "outdoorsy" pack from wall Mart someone had gifted me. Not very bulky, but I can get a change of clothes and some lunch in with room to spare. I don't think a laptop would push it over the edge

But I miss my rack and panniers so much.

Ps, if your bike is set up for it you can easily get by with a thirty dollar rack and about fifty bucks in panniers. Cheaper for sure than a hydration pack that can do what you want it to, and way more versatile.