CSA: I have had a few rough experiences with Czech airlines too (lost luggage, delays) but I can't really hold it against them because they are cheaper than their competitors. I also like them cuz I get the chance of a daytrip to lovely Prague when my connecting flight is not until 6-7 hours after my arrival at Ruzyne Airport (which usually is).
WizzAir: Really annoying absece of a seat allocation policy. They don’t even give priority numbers so entering the plane reminded me of the old days at the school bus when we were kicking each other for who was going to get the seats at the back…. Otherwise a fine service for a £40 (tax incl.) London-Sofia return trip.
Ryanair: Surprisingly I only used them once and it was for a short trip (Edinburgh-Dublin) so I cannot comment too much about them. No major complains other than the annoying Donegal accent of the pilot.
Easy Jet: Their prices have gone up lately I feel. Never had any problems with them.
British Airways: You get what you pay they say, and BA is no exception. New aircraft, fairly (but not always) punctual, and reasonable service. The fact that their food is mingin’ comes as no surprise, being british.
Lufthansa (and Augsburg): It has been a long time and I can’t remember much. Pretty standard and decent service.
Swissair (and Crossair): Top-notch airline. No complains.
Olympic: A delay is a must but it’s the only airline where the food actually made me feel satiated.
Aegean: Great food once more. Fairly punctual.
KLM (and Transavia): Only flew once with them and they lost my luggage.

Can’t blame them though as it was two days after 9/11 and there was a chaos at Schipol, plus my two connecting flights were too close to each other and there wasn’t enough time for the luggage to be transferred. They delivered the stuff 4 days later…
Air France: Really annoying refund policy (but what airline doesn’t have one?). Love the cheese selection on board

. I once bought a ticket (Sofia-Edinburgh) that included an overnight stay at a Paris hotel for the return leg, which I thought was cool.
Fly BE: Small planes, silly luggage policies, great prices.
NovAir: Lllllllovely swedish stewardesses, nice aircrafts, and functional video displays with flight info even for short flights.
American Airlines: Lack of space. Man, did I suffer. It wasn’t my first time on a 767, but I swear the room on the AA 767s is less than normal. And if you are unlucky enough for the guy in front of you to recline his seat, then prepare yourself for a painful 9 hours. Food was not enough for a long haul flight. Otherwise, they are pretty OK.
TAROM (Romanian Air Transport): I was very pleasantly surprised with them. Fairly punctual, nice meals, clean aircraft. I also had to stay overnight in Bucharest airport and I was surprised at how tidy and comfortable it was. Too bad they rip people off by selling a small bottle of water for 3 Euros! Staff was also friendly. There was a mess-up with my luggage and one of them took care of my case personally and re-checked my luggage without me having to do anything. The only bad thing was that when we arrived in Bucharest airport, it took the company 20 mins to send a bus to take us to the terminal, despite (or maybe because of?) the little traffic at that time.
Alitalia: Oh boy. What can I possibly say? It is no wonder that it is universally accepted that they are one of the worse airlines around. I had been warned to avoid them but I thought that these were exaggerations. First they cancel my flight. Then they ask me to collect my luggage in order to re-check it in, but it never shows up. It takes them 3 hours to find the luggage, and this only after repetitive requests of mine. Ground stuff arguing with each other in front of me about whose responsibility it is to find my luggage. Half their employees didn’t even speak decent English. Their aircraft was old, dirty and dusty. I will try to never fly with them again.