Routers
Here's is what you'll need to consider when purchasing a router:
Fixed Base vs. Plunge
- a fixed base router has a stationary base in contrast to a plunge router which has the ability to be lowered into the wood.  Plunge routers tend to be more versatile
 
Horsepower
- the amount of horsepower (HP) a router has will determine how hard it can work when doing tough shaping jobs.  More HP, means a stronger motor.
 
Fixed Speed vs. Variable Speed
- Fixed Speed routers only have one speed and therefore operate at a set RPM.  Variable Speed (VS) routers have the ability to operated a different RPM for different applications.  In general, the harder the router has to work (ex- a deep cut through hard wood) the lower you should set the RPM.
 
Collet Size
- the Collet is the hole that accepts the router bit.   Collet size is either ¼ or ½ inch. The ½ ones come with an adapter to accept ¼ as well.  Router bits are either ¼ or ½ inch diameter shank, so make sure you know your needs before purchasing.  Larger shank bits tend to be more stable in tough cuts with less wobble and deflection.
What will you be using the router for?
- a router is one of the most versatile tools on the market.   Basic router applications include shaping the edge of wood on something like a table top, for example.  Basic operations like that require only a basic router - fixed base with lower horsepower.
- advanced router applications include using the tool inverted in a router table.   This allows the user to do intricate wood shaping, raised panel doors, etc.  A plunge router works very well in a router table.  The type of router table work you'll be doing will also govern the horsepower of your router.  Large cuts like those in a raised panel are harder on the motor and therefore more horsepower is desirable.  3HP and above are recommended for difficult cuts. 
--DeWalt
DW625 3 HP VS Electronic Plunge Router
DW621 2 HP Electronic Plunge Router
DW610 1-1/2 HP Router
DW612 1-1/2 HP Router
DW670 7/8 HP Fixed Base Trim Router
DW673K 7/8 HP Trim Router Kit
--Makita
3606 1 HP Router
3621 1-1/4 HP Plunge Router
3601B 1-3/8 HP Router
3612 3-1/4 HP Plunge Router
3612C 3-1/4 HP Plunge Router
--Porter-Cable
9690 1-1/2 HP Router
100 7/8 HP Route
690 1-1/2 HP Router
7518 Speedmatic 3-1/4 HP 5-Speed Router
7519 Speedmatic 3-1/4 HP Router
97529 2 HP VS Plunge Router
7529 2 HP VS Plunge Router
693 1-1/2 HP Plunge Router
7538 Speedmatic 3-1/4 HP Plunge Router
--Bosch
1601A 1 HP Router
1602A 1-1/2 HP Router
1604A 1-3/4 HP Router
1604AK 1-3/4 HP Router Kit
1606A 1-3/4 HP Router
1615 3 HP Plunge Route
1615EVS 3-1/4 HP Plunge Route
1614EVS 1-1/4 HP Plunge Router
1613EVS 2 HP Plunge Router
 --Hitachi
M8V 1-1/2 HP Router
M12V 3-1/4 HP Plunge Router
TR12 3 HP Plunge Router
--Milwaukee
5660 1-1/2 HP Router
5670 2 HP Router
5680 2 HP Router
5682 2 HP Router