I've been going to Sip Dao Thai for several years now, and it's my favourite Thai restaurant. I still try other thai restaurants occasionally, but I'm usually disappointed. Sip Dao are the best. The food is great, and the service is some of the friendliest I've ever seen. I eat there a couple times a week when I'm able.
They are willing to really customize the spiciness to your preferences, and if you say you want five star, they'll give you thai five star. If you want zero star, they are able to make it so it still has flavour--my friends have been very happy about this as well.
They prices are pretty affordable, and they now have a great 15-percent off deal on Mondays as well!
I especially recommend their curries; the green curry is awesome and the panang is to die for. Any of their dishes are great, though.
Please keeps these guys in business, they are really awesome. ^_^
Also, they now have a second location called Thai Destination in Fairwood. Last I checked it was open Sundays, so now you can get your Thai food fix any day of the week.