A common issue when it comes to effect pedals is the powering. Sure, you can use separate power supplies to each pedal, but if you´ve got a bunch of them this will lead to problems with the mobility of your board. Each power supply would need it´s own power jack and force you to invest in a lot of big power switches. Plus, this would take up a lot of space.
Another solution is to use batteries, but hey, that´s not a very good solution in the long run. Many pedals eats batteries as the cookie monster eats cookies, and even when the pedal is not switched on, it will feed on your batteries as long as the input cord is attached in the pedal. It´s a real waste to use batteries in the long run, but in some occassions it comes in handy. When I´ve got small gigs at small clubs with tiny scenes, and really short suondchecks, I´ve found it dumb to plug in a giant pedalboard which would take up more space than available onstage. At these circumstances I usually get out three necessary pedals (most often some overdrive, delay, flanger, chorus or a booster) and get them running on batteries. This makes quick scene loadings possible and doesn´t use up that much space onstage. The only downside is the risk of kicking around pedals when they´re not attached to a board, and of course the sonic possibilities gets smaller with less pedals. A really important thing here is to have fresh batteries in your equipment, so your great sounding overdrive pedal won´t run out of steam in the middle of the gig, leaving you with a thin, clean sound when you need to rock like a hurricane.
The best option is a power supply which can power a lot of pedals without any fuss. There´s a big market for this type of equipment and before you run and get the cheapest one there´s some things to think about, What kind of pedals do you own? Do they run on different voltage? The most common for guitar pedals is to run on 9V DC, but it´s not likely that every pedal you own does this. For an example the Boss BF-2, an old, great sounding flanger pedal, needs and 12V ACA adapter to get going. And there´s other pedals that needs as much as 18V or 24V DC. Some pedals comes with their own adapters and shouldn´t be used with others, and if they´re expensive ones it´s not worth taking a chance and plug them into something else. When it comes to my Hughes & Kettner Rotosphere, I use the original adapter, just to be on the safe side. Hooking pedals up with wrong power can damage them, or even worse, destroy them, so be sure to read what they need to work. Most pedals however can be hooked up to a power supply if you just do it right. Be careful and plug them in to the right kind of voltage and you´ll be fine. The bottom line is: you will probably need a power supply which can power up different kind of voltages, so don´t get one that only serve 9V DC pedals.
Then there´s the issue of ground loops. Ground loops creates noise, and if there´s one thing guitarists don´t want it´s uncontrolled noise coming from your amp. To avoid ground loops you´ll need a power supply with isolated outputs. Power supplies that uses this solution isolates every output so each pedal will run on it´s own without connecting with other pedal´s in the chain. It´s like the solution I talked about earlier, to have a lot of separate adapters to each pedals and then connect them to the same power strip, but without having all those big adapters cramming up space. Instead all the power cords will go neatly into your power supply and save you a lot of space and weight.
There´s solutions to most issues if you just get your facts straight. I own some pedals which I´ve had to do some research with to get them to work with my power supply, but in the end I´ve been successful. Two examples is the ProCo Turbo Rat and the Janglebox. Two awesome sounding pedals but without the standard 9V DC voltage. The Janglebox needed a special cord to hook it up with my power supply, the Turbo Rat needed a adapter cord to get it on board. So I got these parts and now we´re all happy. Nowadays nearly everything is on the Internet, so if you´ve got a problem or a question - Google it! The answer will probably be out there at some forum.
So, which power supply will meet all these demands? There´s probably some more out there, but I found the Voodoo Labs Pedal Power 2 to be a real friend. Isolated outputs, different cords for different voltage and switches between 9V and 12V. It can power 8 pedals and also have some specials, like the "sag". This is a thing that could, if you want, simulate the sound of your pedal when it runs low on battery. Some pedals sounds really great when sagging, and therefore this feature could be interesting. But the best thing about this product is that it can power up most pedals and does so without adding any unwanted noise due to ground loops. It costs a bit more than certain other power supplies, but you´ll get what you pay for. In this case you´ll get a great power supply which, if proper used, won´t let you down.