I agree youtube is a good source for sound samples. One other important thing you must concider is the amp if the amp is poor, any pedal might sound bad, too. Pedal in your signal chain makes you play differently. It also adds noise to you singnal chain; more pedals, more noise. In recording environment I try to keep my signal chain as clean as possible. One option is to use pedals with true bypass. Commercial pedals don't have true bypass. I have way over thirty pedals, but eventually I'm in a situation my main effects board consists only DIY clone pedals and a tuner. I stay away from multieffects and digital, because my opinion is they sound quite weak compared with analog. Also, as a fan of distorted sounds I have four different od and fuzz pedals and I have a loop pedal on my board(s) which ables me to add more effect if needed. After I switched to true bypass pedals I could throw away the noise suppressor from my rig
Check out
General Guitar Gadgets. They are selling kits, but there are also loads of projects to build. The prices are reasonable and pedals easy to build (if you can solder). Almost all of the pedals are true bypass. Best of all, these pedals sound awesome. My favourite DIY pedals at the moment are Orange Squeezer comp (for
lapsteel and slide), Marshall Blues Breaker, ITS8 (tube screamer clone), Dallas Rangeblaster (treble boost, Brian May type), Red Fuzz, EA-tremolo (incredibly good tremolo with good sounding pre), Tycobrahe Octavia (fuzz with octave down), P45 (MXR phase45 clone) and Reverb. Pedals I also use a lot are also 60's
Boutique Fuzz Face, Big Muff, Schaller tremolo, DOD FX-909 analog delay, Yamaha E1005 analog delay and Ibanez Auto-Wah. Not a pedal, but otherwise a great effect is the E-bow.
Still, everything starts from the combination of guitar, amp and what you play. There is no point buying pedals if you don't know how they react with your rig, on the other hand if you don't have have the pedal it is impossible to try it out. Borrow pedals from your friends to try out with you guitar and amp, or take your guitar to the music shop and try to find an amp that you use.
Still, I would stay away from chorus even though I do have Boss CE-300 Super Chorus and a C-2 in my home studio.