|That's a pretty subjective question. Ask 5 different people what their favorite router is, chances are you'll get 5 different answers.|
I've had the combination unit that is a modem/router/wireless access point all in one and didn't like it. So when the wireless in it stopped working properly, I got my ISP to send me "just a modem" as I have my own router. What you get is going to depend on what you'd prefer. A separate modem/router isn't that complex. Phone line goes into the modem, network cable comes out of modem and into the "internet" (external) port of the router. Clients plug into the LAN port(s) of the router.
In this day and age it makes no sense to not buy a wireless capable router. Even if you don't have any wireless devices now, chances are you will very soon. Based on that I would suggest you look for a wireless capable router with dual radios so it can operate on both the 2.4 GHz and 5.0 GHz bands. You'll want it to be at a minimum wireless N and I would also recommend you get one that has 4 LAN ports that are all Gigabit.
Do some shopping around, read reviews (very important) and then make your decision based on features and cost.
My suggestion is to
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.