Faites phi-phi ici

"The fool repeats his own mistakes; the wise learns from his own mistakes"
-old proverb, or a tradition, or an old charter, or something
Well, the even wiserer learns from other people's mistakes, and so, hear ye hear ye:
-If you want to go snorkelling, do so in a beautiful, secluded area undisturbed by thousands of tourist currently also snorkelling there
-If you want to go snorkelling, do so in a place that hasn't been ruined by years and years of millions of thoughtless tourists touching the sensitive marine life, spewing their engine waste and littering
-If you want to go snorkelling, do so before you go scuba diving for six days in beautiful national parks. To go snorkelling after such a majestic experience is quite the anti-klimax.
-If you want to see the awesome rocks, beaches and jungles of Koh Phi Phi, do so in low season, and go there for a couple of days/nights; that way you can at least get a glimpse of how the place would look without the billions of daytripping tourists covering the place in mid-day
-If you want to experience the awesomest beach on Koh Phi Phi, get thee a time-machine and return to any year before the Leo DiCaprio film 'The Beach' was released before going there
In short, don't do a daytrip to Koh Phi Phi.
That being said, a more or less obligatory tickbox is checked, and I have to admit that the land- and seascape was amazingly beautiful underneath the layer of tourists.
Phuket Town, however, suffers from no farang fever. Most Westerners tend to bulk up at the vast beach resorts scattered throughout Phuket island, leaving the town refreshingly devoid of tourist traps, enriching its local atmosphere. The Old Town is quaint, with its interesting Sino-Portuguese architecture, and the night markets will get your belly full and satisfied for less than 50 bahts. And I highly recommend the place where I was staying: Ananas Hostel, located (once found) in a well-kept, guarded area some ten minutes' walk from the city centre. Very clean, breakfast included, extremely friendly and helpful staff and excellent wi-fi. All for a cheap penny.