i agree with Benny

texture mapping will save your life
you can make textures in Maya, but like everyone says you should paint a texture (the are just images like jpg, tiff, etc), esp if you dont want to model the letters on the keyboard (afaik Maya doesnt come with a text->pokygon thing like swift3D)

you dont particularly need photoshop, it just so happens that photoshop is the artist's choice over Corel Paintshop Pro, and MS Paint
heck, you could learn the image format and write a program in java or C# to draw you a picture (of course you gotta be pretty damn good at picturing things without knowing what youre doing)