The Four Major networks are available OTR (over the air) with an antenna. Additionally, at least in Columbus, CBS is available as a live feed over PSVue. The other four networks currently only have their online content. However, ALL channels on PSVue give you access to all of your subscribed channels' online content in addition to the live feed. This removes the need for a DVR in most cases, as you can watch any show after it's aired. Another bonus of these services is the month to month flexibility. If you only care about the sports channels during certain months, you can add them or subtract them for any given billing cycle. BTN, Fox Sports Ohio, et al are included in the bigger bundle on PSVue. Additionally, you can use your PSVue login credentials for any specific channel's app (e.g. BTN's roku app, android app, etc) and access content on your device of choice, or say a buddy's house if he wishes to watch a certain channel's content (cough* split the cost *cough.)
I'd recommend a Roku, PSVue, a digital (Mohu leaf and other fractal antennae are good) antenna for OTR major broadcasts, and the Roku channel XTV - a free channel with a ton of content, live streams, but not always HiDef. If you are looking for a way to record Non-Shows on major networks (news and such) check out an HDHomerun tuner. It'll hook up to your antenna, and give you recording, watching, and playback options via its roku channel.
There are several other options, jailbroken firesticks will give you a truckload of content. Plex allows you to roll your own media server...it's all in how far down the rabbit hole you want to go.