Sub and surrounds

My current set up is a Marantz AV7005 powered by a Mac MC205 driving SF Liuto towers and matching center. Since I mainly watch movies, I was told I should get surrounds and a sub. What surrounds and sub would you recommend without breaking the bank?

Your absolute best match will be a pair of SF Liuto monitors or a pair of the SF Liuto Smarts. Looks like the Smarts will give you more placement flexibility since they come with wall brackets and can be used horizontally or vertically. I would definitely use a SF speaker.
Thanks, I was talking with a friend and was told it doesn't matter what you have back there since its just back ground noise. Any thoughts?
In the very early days of surround sound with only Dolby Pro Logic, the rear channels were mono, limited bandwidth, and even less power than the front in the A/V receivers. In that case I would say rear channel speakers might not be as critical as the front. Today is a totally different story since 5.1 surround sound is 5 discrete full bandwidth channels with a separate subwoofer channel. Take a look at the picture here,

Obviously that jet would sound the same, front or rear in the room with another pair of SF Liuto towers for the rear, and some people would do just that. The next best thing is my previous recommendation. As you keep dropping quality and/or moving to another brand, then that 747 jet on the front may sound like a 2 passenger prop aircraft on the rear. Matching the rears with the fronts will give you a better balance to the sound throughout the room.
Many good subs are available these days. I prefer sealed designs over ported, but since your needs are mainly movies a ported design would not be a bad choice. I've owned SVS and Hsu and can recommend either. Your pre/pro will handle a pair of subs, so I would take advantage of that if you have the floor space. Two subs versus a single can yield a smoother frequency response over a wider area.