Since you asked for helpful plugins: The Redirection plugin by John Godley has some logging abilities, and the 404s log shows me what page folks are trying to access and their IP (and the date & the referrer). I'm not sure where that falls on the "user-friendly" continuum, but it's much better than nothing. (I manage a small, niche website that focuses on providing free information -- it's not a complicated setup. Comments aren't even allowed since they are usually misleading or off topic (or both) questions on well-researched articles -- and it was easier than handling spam, and people can and do just email the website management instead of commenting.)