really all depends on what you want, i haven't been in a long time. a lot of the main shops have their seed origins listed and thc %, so i'd just roll with the highest thc count .I might go amsterdam in a month, what are the best "weeds" for a moderate smoker to try?
personally, i'd rent a bike and travel to the outskirts. get out of the tourist area and the weed gets surprisingly better.