Would a typical wifi router handle streaming videos from a home server while also handling standard internet traffic? Can I watch a movie and surf APS at the same time? Doing that in my current set-up causes lag issues.
Ideally, I'd like to load all of our DVDs onto a dedicated computer/server for easy viewing and then be able to send videos to different areas on demand.
Can current wifi routers be reasonably secure?
I like the ease of wifi connections, but I don't want to have to constantly change batteries on remote devices such as security systems.
I've got a plex server running on a Diskstation DS211j. I can stream off that while watching anything I've ripped to it just fine, and if the attention deficit urge takes me, start watching YouTube clips or something on my laptop while watching things off the media server simultaneously with no problem. The DS211j does have a gigabit interface on it and is plugged into my gig switch, as well as my Samsung bluray player with plex client software on it, so I get full gig bandwidth between those devices due to my gig trunk going from my office to my living room. However, I also have the plex client (as well as generic DLNA client capability) on my laptops and android devices, and I can walk around and with a good wi-fi signal I can stream off the DS211j anywhere on my property with no lag issues. My android tablet has problems sometimes but that's due to what seems to be a crappy wi-fi card in that particular device rather than my network, since my laptops have no problems anywhere.
Look into a Synology Diskstation. I'm getting ready to upgrade my DS211j to a more powerful unit... probably a 412+ but possibly a 413. The 412+ has much more CPU power for doing on the fly transcoding if there's a playback codec issue on the client device, and has 2 more bays than my current little device, as well as a gig of RAM rather than my pittance of 128MB.
Even the tiny little DS211j has been an awesome unit, though. Does a lot more than I would have considered possible from a 1.2ghz ARM processor and 128MB system. I've tested doing multiple streams from the DS211j, and I've gotten 3 different clients playing 3 different shows with no problems, two of them wifi and one on gigabit wired, no issues. I'm reasonably certain I could handle 5-6 simultaneous streaming connections at a 480p bitrate, 3-4 at 720p. A system with 4 drives rather than 2 would have considerably more IO power and probably could handle a dozen or more simultaneous streaming media connections.
Wireless security... I run MAC address exclusion on my wireless network. If your MAC isn't in my allow list, you're not getting on wireless. As well as WPA2. It ain't bulletproof, but I've yet to detect anyone compromising my network.
The new 802.11ac routers (assuming you have 802.11ac wireless adapters on your devices) will handle streaming HD video (by HD I mean recorded HD broadcast TV, full bitrate bluray rips, etc.) just fine. Wireless N can do so, but if you don't have a very, very good signal it can struggle.
Most of my media is stored at 720p quality, and I stream it wirelessly to client devices over 802.11n in the back half of the house via that access point, and 802.11g in the front half of the house on a separate access point. No problems from either AP. Bandwidth graphs when running 3 devices show the Diskstation is using about 20-25mbit per second throughput of its gigabit interface. The bottleneck is the disk IO system, which on this RAID1 system will probably serve a maximum of 40mbit on such a low powered CPU.