I really like this Donner Power Supply. Costing around $35 buck, it is a no brainer. It comes with everything you need to hoop up just about any guitar pedal to it, including a rare 3.5mm adapter and a polarity reversal adaptor. It will power eight 9v pedals, including one 500ma pedal, one 12v pedal, and one 18 volt pedal. This power supply will suit the needs of 95% of guitar players. Are there "better" power supplies out there? Yes. Do they cost 5x as much? Yes.
I have a ton of pedals and for various reasons end up putting a couple pedalboards together each year. Whether it be me redoing a pedalboard or building one for a friend, this style of pedal power supply has been great to work with. I really like the option to have the led lights on or off too.
This is actually the second Donner Power Supply I have owned. The first one I used for a bit and then ended up giving it away to a guitar player who did not have a power supply. I am really glad I have a second one! I highly recommend this to anyone that does not have a power supply or needs a second.