rome vs istanbul?? from a foodie standpoint
You should probably look at parlafood.com. Katie Parla lives in Rome and goes frequently to Istanbul. Surely something on her blog will answer your question.
Off the top of my head I'd say if you like spices go to Istanbul, if you are more interested in the best fresh produce, choose Rome. I'm prejudiced in favor of Rome, where I live, but have enjoyed my limited gastronomic adventures in Istanbul. You need not to mind crowds for Istanbul.
Is this not the same asking apple-v-pear?
Difficult question (not least as I've never visited Turkey). My inclination is Istanbul as I enjoy eastern Mediterranean food and it would be a new experience. That said, I would probably get by better in Rome as I speak a (very) little Italian and am more familiar with Italian restaurant speak.
To my mind there are two kinds of food, bad food and good food regardless of geography.
I'm quite sure it's possible to get both in either city.
For me i would go to Istanbul, only because I have been to Italy many times and have a far greater familiarity with Italian food in terms of both eating and cooking.
This is an impossible question to ask as the cuisines are so vastly different. While I adored Rome's gelato, I had a far better food experience in Istanbul... but that is only because I HATE cheese and much prefer Middle Eastern anything to Italian. If you go to Istanbul, seek out the pides (Turkish pizza) and the elusive pistachio kebab (a friend had it but alas I could not find it.) Do go to a turkish hammam- it's worth the torture:}
Quite different cuisines.
Istanbul has better seafood.
Rome has more variety, specialist food stores and better restaurants. It's easier to find good food in random restaurants in Rome than in Istanbul where most local restaurants serve overcooked, overstewed and oily food. Istanbul does have good "eats" but you must look for it.
Both have lovely food markets, especially outdoor ones so it's easy to cook well at home.
On the whole a serious cook will be happy in either city so you need to decide on the kind of food that interests you and which you want to explore (Italian versus Turkish/Middle Eastern).
re: Roland Parker
+1 on Roland Parker's response. I have spent a lot of time in Istanbul and absolutely love the food there, but if you want really good, seriously interesting cooking you will have to seek it out and go at least somewhat off the beaten path. There are a lot of restaurants that serve more or less identical menus, although I will say that the lowest common denominator in Istanbul is still higher than it would be in other places.
Check out the food blog Istanbul Eats. I have gotten some very fine restaurant picks from there. It will also help a lot to get friendly with people in Istanbul who really care about food--they can direct you to little places you'd have trouble finding on your own. Luckily, Google Maps has Istanbul covered, so you can pretty much find anything that you have an address for. And the absolute best time you can have in Istanbul is wandering around the backstreets anyway. Getting off the beaten path in that city is essential.