I've seen similar issues in other homes. It sounds to me like the pressure from your municipal water system is just too low. In many cases this is just something you have no power over, but talk to your neighbours and see if they're having similar problems before you go spend a bunch of money on your house.
If your neighbours are also seeing similar things then contact the city. It may be a maintenance issue with their equipment, or perhaps the pressure is just turned too low. The city will often change the pressure to each neighbourhood during different stages. For instance during construction a neighbourhood is usually kept at higher pressure, then the pressure is lowered. It sounds like your area isn't under construction, so its possible they have maintenance issues, or perhaps someone turned a valve just a bit too low.
Once all this has been checked out, then I'd say you should check your own house. The above steps should only take a couple of days, and might save you hundreds or thousands of dollars.