I've read both your comments, thank you, the second one was a little above my head and interest for more speculative alts right now, that is a fully air gapped setup. Hence the reason I was curious about my initial question. A PC updated and maybe even using linux and nearly 99% offline for maybe 5 or so alt coin types with lower levels of investment and using only the dev recommended wallets. Only to be network connected to transact to and from an exchange and off again? Just wondering if that's a "decent" amount of security assuming I don't mess it up with poor installs.
Using linux is always a good Idea. About 96%+ of Malware is written for Windows.
If you are using linux, do keep your pc offline almost all the time
(you also should not plug in any "non-trustworthy" usb-devices anymore), keep it up to date
(best approach would be to download linux update on another online-machine, then copy it via local network onto your wallet-pc, verify it there, then install it), you should be quite fine with your setup.
Assumed the wallets you use do not contain any backdoors.
I'd recommend a Hardware wallet (e.g. trezor/ledger) for your Bitcoins and (most common) Altcoins. Its more secured and easier to handle.
I can't advise you on keeping the system offline for most of the time, since that means that you won't be having security updates and patches. That works when you have it offline 100% of the time, but if you just pop it online for a short while, it might not even get a chance to catch up before it gets infected with malware.
Well, its possible to download updates on another machine, copy, verify and install them.
And most linux distributions are not contacting 100 web services and creating 600 http requests before the OS is ready to start internet explorer