Polk Monitor 50 towers are the same speakers as Monitor 40 bookshelf units, only the enclosure is different. If you want to try a setup without a sub initially, consider the Monitor 70 towers for their better "low end".
Matching "all four" vs. "fronts and surrounds" is a matter of what type of listening you want to do. If you like multi-channel music, like DVD-A and SACD, then matching all 5 speakers is a definate plus. If you are primarily into movies, then the surrounds can be different from the fronts because surround soundtracks carry very little critical audio information to the sides and rears, mostly ambient and positional audio effects. For a movie HT setup, Polk Monitor 30 bookshelf speakers would work fine for the surrounds.
If you want to consider towers for 4 HT speakers (no stands or furniture needed), the consider Monitor 70 for L & R front, and Monitor 50 for side surrounds in a 5.0 setup. The CS2 center is the match for Monitor 70's. The CS1 is the match for Monitor 50/60 fronts.
On the receivers, if you don't need a "Zone B" output for remote speakers, then consider the Denon 590 or 790 receivers (very like the 1610 and 1910 but no zone B). The Onkyo SR507/607 receivers will also be a good choice.
Matching "all four" vs. "fronts and surrounds" is a matter of what type of listening you want to do. If you like multi-channel music, like DVD-A and SACD, then matching all 5 speakers is a definate plus. If you are primarily into movies, then the surrounds can be different from the fronts because surround soundtracks carry very little critical audio information to the sides and rears, mostly ambient and positional audio effects. For a movie HT setup, Polk Monitor 30 bookshelf speakers would work fine for the surrounds.
If you want to consider towers for 4 HT speakers (no stands or furniture needed), the consider Monitor 70 for L & R front, and Monitor 50 for side surrounds in a 5.0 setup. The CS2 center is the match for Monitor 70's. The CS1 is the match for Monitor 50/60 fronts.
On the receivers, if you don't need a "Zone B" output for remote speakers, then consider the Denon 590 or 790 receivers (very like the 1610 and 1910 but no zone B). The Onkyo SR507/607 receivers will also be a good choice.