Personally, I don't see much point in stocking up on meds, unless there is a specific need (although admittedly my LFS is literally 2 minutes away from me, so emergency trips are not an issue). In 7 years of fishkeeping, I've only now needed to buy any meds (swim bladder treatment), as I've never really had any diseases to deal with.
Maybe I've been lucky, but I believe that if you keep your tank in the best condition possible, quarantine any new fish before adding them to your tank, and give your fish a good variety of food, then diseases and the need for meds should be few and far between. I also prefer a natural approach, and really shy away from dumping chemicals into a tank unless I have to (water conditioner aside, of course!). But maybe that's just me.
If you've got money to burn (lucky you!), then I would suggest you get the following, if you don't have them already:
Spare heater & filter (Sods law, if your main ones fail it'll be on a Sunday just after the shop has closed....)
Quarantine tank (around 5 gallon or so)
Aquarium salts (a lot of meds go together with this, and has a lot of use by itself)
Spare air pump, hoses and airstone
Decent liquid testing kit