I have a few domains where I plan to take the VPS server that hosts the content offline.I will be keeping the domains.What is the general best practice regarding the DNS A records?I'm assuming once I delete the VPS the hosting company will reassign the IP address of the VPS to another server, and if my domains DNS records are still pointing back to My old server, it might look like I am hotlinking My domains back to that old server!Also out of consideration to the person taking over the IP address server I dont want them to have to deal with the constant bots probing My domains (although much of that traffic probably is directed straight at the IP address itself and not the domains - which I dont control).Is there some kind of proper DNS entry you can assign for an A record when the domain doesnt have a webserver? 
I am taking the web server for a domain offline - but keeping the domain - what should I do with the DNS 'A' record?
dns
I think that generally depends on how much you care about any value you have built up over the years.If you want to preserve any value of the sites, then you do want to at least put up a place-holder website and handle incoming links. Keep in mind that removing your content will cost you a down-grade in future performance, but at least having the domain name resolve to a website and handling the inbound links should preserve some value.I would especially recommend this if you intend to resurrect these domains or sell them.Otherwise, it would be okay to delete the A record or have your registrar park the domain which may be better than no website at all. If you are just going to let the domain names expire, I would simply delete the A record and be done with it. Do not forget MX records and any PTR records. I have done this with the thought that the domains would just expire in time.