wowww!!! i love delays/echo to the verge of being addicted to them! hehehehehh...
ok, 1st off i think u need to know what u r using it for. if its just for just simple slapback delay or normal delay usage without a need for accurate tempo/repeat timing, then a Boss DD3 or Ibanez DE7 will do. the DD3 is very "crisp, hard/harsh sounding" to some, whereas the DE7 has got option of analog/echo sound for "warmer sounds." but the downfall for both is, the delay will stop as soon as u switch-off/stomp-off on the pedal. meaning the delay trail will abruptly stopshort.
to counter that there is the Boss DD5 (discontinued) and DD6 and Digitech Digidelay. these pedals will let the delay effect to trail-off even after u've switched them off. no abrupt cut on the delay trails like the DD3 or DE7. and they have an option to do tap-tempo too! what is that? well, that is the option of setting ur tempo/repeats by tapping. this results in accurate delay times as oppose to "guessing". the Digitech Digidelay have the option of tape/analog delay sounds too. suppose to sound warmer.
if u need a few delay presets at one time as appose to just one delay, u can try the Boss DD20 or Line 6 DL4. i have not tried the DL4 but it seems great from reviews, but needs hand/ears on for me to judge. i've tried the DD20 and i loved it. u can have 5 pressts (i think!)and different delay sounds (echo, tape, etc...). but the downside is u have to scroll through the presets to get to the one u need, as oppose to having one button for each preset, like the DL4. but that is a small matter as who will change a few different delay sounds in a song? hmmmmmm... maybe there is.
anw, try before u buy. coz u might have diffrent needs/ears. hope this helps... sorry for the long post tho...