The formula for calculating Amps from Watts is I=P/E, where I = Amps, P = Watts and E = Volts. So five 55W halogen lights draws ~23 Amps, five 100W halogen lights = ~42 Amps, while five 35W HID lights would draw only ~14.6 Amps.
All things being equal, more Amps = more light, so a 100W halogen will be brighter than a 55W halogen. But HID's use different construction to provide more light with less power, so a 35W HID will be brighter than a 100W halogen while consuming less power than the halogen.
As your Amp draw increases, so must the ratings of all the components, such as relays, sockets and wiring. Assuming you have to run 10ft of wire, (wire length also matters), you would need to use 6AWG wire for 5x100W lights, 8AWG for 5x55W, and only 10AWG for 5x35W. I use the chart at this web site for figuring wire size: http://www.windsun.com/Hardware/Wire_Table.htm
. From personal experience I can tell you that working with 10AWG is difficult enough, being the limit of all crimp-on connector's I've seen and tough to solder. I've run some 6AWG to the back of the Jeep for an Inverter and power outlet and I had a hell of a time soldering the connections.
As for battery capacity, it shouldn't even be a factor when adding lights, as you wouldn't want to exceed the alternator's capacity for more than a few minutes. Depending on your year and model JK, your alternator puts out either 140 or 160 Amps at 2,000RPM, and the engine, standard electronics and stuff draw around 30-40Amps, so you have around 100Amps reserve capacity in the alternator. If you exceed this draw you will then start tapping on the battery, which can rather quickly become depleted. You can add a second battery -- and if you do it needs to be tied-in to the charging system with a dual battery charger/isolator -- but this only extends the time before both batteries go dead. You shouldn't design a lighting system that exceeds the output of your alternator.