Great design, thai cook Sumudu, nice food and affordable price makes a great combo for a nice evening or daytime meal. Make sure to book a table in advance, or order a take away (which should also give you a discount).
It's central, it's cheap, it's good - what else do you need? Just around the corner from central square, this place has a great casual vibe. Also, all the staff speak excellent English, and will always ask you how your curry was.
Did I already mention takeaway discount?