I like Renaissance Art journals, personally... They get rather expensive when you're looking for something with more than 200 pages though... best I could find was this one
Large Leather Journal - 216 pages for what you were asking. The refillable journals might be better for journaling, RenArt has those too... Moleskines are pretty nice too, but they don't meet the 300 page requirement... or the slightly thicker lines... or the good quality paper part either, for that matter...
