Don't do it! Pure insanity to want to make your own espresso at home, think of all the money you'll be taking out of the economy. If people find out what espresso is supposed to taste like who will give all those kids jobs to act like they know something about coffee and espresso?
If you insist to get into this home espresso thing then take everyones advice and think grinder first. Single Boiler/ Duel Use will make tasty espresso, the cult like following of Sylvia scream this, but they will not be making you many drinks very fast. HX machines will take care of as many drinks as you want and you will never have to wait for the machine, learning the cooling flush with an HX allows control over brew temperature. Double Boilers won't make a better espresso shot then an HX or a PID'ed single boiler (which will cost as much as an HX machine) but many allow you to set the desired brew temp and will have enough steam power to froth a few gallons of milk.
Have fun researching
