Is it wise to use analog input pins to read digital buttons? I am thinking about building a circuit that is literally going to take 11 of the 14 digital pins of an UNO to communicate with an SD card and an external EEPROM chip (EEPROM programmer).

Using 4 shift registers and the SD card, I will have 1 digital pin left.  Well, I'm also reserving pins 0/1 for serial communication.

Anyway, I need to read some external buttons and I have the 6 analog pins that I haven't touched.  

I will only need about 4-5 push buttons in my design so they should fit nicely on A0+.

So, my question is, will I run into any issues doing this?  Or, are the analog inputs better left for true analog reading?

Thanks.
The Analog pins are essentially identical in functionality to digital pins when used as digital I/O.

If desired you could "be clever" and use an analog input in analog mode to read multiple keys using one pin. eg using 10k, 22k, 39k, 82k, 150k in series with 5 buttons from V+ to pin and a say 4k7 to ground would result in 5 voltages which were easily distinguished using an analog read. This is a very very old technique indeed and allows far more than 5 keys on one input pin. THere are limitations which can be discussed if required. 

R1 ... R5 correspond to buttons 1...5

Vout = V+ x Rb / (Rb + Rbutton)

Example only  

Rb = 39k
R1 = 10k
R2 = 22k
R3 = 39k
R4 = 82k
R5 = 150k

Gives   


The % of V+ in column 2 when a button is pressed.  
The voltage in column 3 with V+ = 5V 


Delta-V is the difference between that key and the one below - very ample clearance.