Just a few suggestions...
Marche on Randolph is a loud, vibrant atmosphere - pretty good french/american food, interesting carnival or "circus-y" decor, like umbrellas used as light fixtures. Had a birthday dinner there and it's a festive place for a celebration.
Cafe Iberico on LaSalle is also a fun place to try lots of little plates - order a pitcher of sangria, order tapas one by one (or in a bunch, but be prepared to have not enough space on your table) and feel free to take your time. While it's rather bustling in there, I've never felt rushed to leave.
In the same vein, Cafe BaBaReeba (Halsted) is another fun tapas place, but to me it seems more expensive with fewer choices. Just one opinion.
Living in Bucktown, Cafe LaGuardia is a nearby option for mojitos and fairly standard Cubin/Latin food. No real stand outs for me with food - although I do enjoy the plantain nachos - but it's a fun sorta retro lounge (think leopard print and red christmas lights) and some couches to lounge on by a fire.