In the good old, bad old days, trying to choose a graphics card was easy - you just looked for the fastest card you could afford and then tried to find one a little faster. Playing games (as I was then) was a marginal affair that would push a computer to the limit, and anything that could be done to increase speed helped - when playing mechwarrior, it was not unusual for the system to suddenly slow to about 1 frame a second briefly, while missiles were being fired, and you had to guess at where the target would be.
That was then.
I've not gamed in probably 5 years, but I do manipulate images, and have found recently that as various operating systems bloat, having a browser, email client and full-featured image editor open can bog the whole thing right down. I've been looking at budget cards, but they all (still!) have 64 bit memory bandwidth even though they have 1 or 2Gb RAM onboard. TBH I have no clue anymore what's good, and the reviews are solely interested in gamers it seems, where a budget card starts at about £70. If I DO buy a card it will be like sticking my hand in a barrel for a 'lucky dip'.