I totally agree that a POS is really important to have. It just sets the tone throughout your restaurant of being a professional, slick, outfit.
One service that we've been using for just a couple of months now is Save My Table (I think the address is just
Save My Table | Restaurant Host Stand Software), but it's allowed us to take on-line reservations really nicely - but also it manages our entire dining room seating. It tells the host where to seat each party, and gives them estimated seating times too. We've been really impressed with it so far.