Hi Papabravo,
I feel at my 61+, the it is reasonable that we go for normal components like 7805 or 78L05 as regulator and standard DIP packages untill we complete the project to a workable stage. if later bulk assy is required and SMDs are to be used as , so called state of art , or for minaturization, it would be better to train a junior and get it done then we suffer the issue-- for eample, i am now soldering a DDS chip (ssop28 from analog devices) in its position. Because i suffered -ve sight earlier and now the readings are near ZERO, but for sperical power being on negative side, I am able to manage. May be if your eyesight was very normal earlier you are now likely to have +ve power glasses.
as far as regulators are concerned, whether you use 3.3V or 5V as Vcc, depending on the Controller used, LOw drop ones caould be used if equipment is run on cells (6V or 4.5V) or even 9V. as at low power consumption the entire capacity of cells can be made use of. Otherwise in case of normal 5V regulator you need to maintain a minimum of 3V difference between input and output. this is well possible in Adopter (wall wart) based power supplies.
All the best.