I hope you are relatively young, and I hope you have the wisdom to pretty much ignore all this advice. Except mine, of course. Start low and slow and listen carefully at each step in your system development. Add and then take away in order to get a bead on what does what. It takes several years to gain a command of the hobby and of how to get where you want to go, and only you can do the work. It doesn't hurt to learn something about electronics and acoustics along the way. Read books.
Basic questions: Do you think you prefer tube devices or solid state? Turntables typically employ one of 3 types of drive systems: Belt, Idler, and Direct. Each of these types of drive system imparts a certain characteristic sound; decide which you prefer. Etc. I would definitely NOT start out by investing in expensive power cords, as you mentioned above. Just make sure your power cords are better than lamp cord and are of relatively thick gauge (For example, Loew's sells 12-gauge power cord that many say sounds great for very little money), and then worry about the rest.
Basic questions: Do you think you prefer tube devices or solid state? Turntables typically employ one of 3 types of drive systems: Belt, Idler, and Direct. Each of these types of drive system imparts a certain characteristic sound; decide which you prefer. Etc. I would definitely NOT start out by investing in expensive power cords, as you mentioned above. Just make sure your power cords are better than lamp cord and are of relatively thick gauge (For example, Loew's sells 12-gauge power cord that many say sounds great for very little money), and then worry about the rest.