I'm planning to Manila end of november. Any suggestions on what and how to do in 4-5 days manila trip? such as nightlife, nice places at manila outskirts... beaches.... diving, etc.

Well for sightseeing go to Intramuros and Rizal Park then go to Baywalk in the evening. For nightlife there is the Fort Bonefacio club scene with embassy the most prominent club. Malate has many live music clubs.If you are after the other adult entertainment scene then Roxas Boulevard in Pasay and Padre Burgos in Makati is your best bet. Otherwise I think 4-5 days is a short time but probably go to Batangas, Puerto Gallera, Lake Taal, Tagaytay or even Baguio for a few days. Two days in Manila would probably be enough, unless you want to experience more of the nightlife scene.

#1...alas Baywalk is no more. The Honorable Mayor "Dirty Harry" Lim had it closed down on account of the noise from the music kept guests in nearby 5 star hotels awake (surprisingly the noise of traffic doea not disturb them), or maybe cos the owners did not (as yet) subscribe to the Mayors Xmas box....
Agree with your other suggestions, and would also suggest Antipolo at sunset for a view over Manila (though best to have a car and driver), maybe do the day trip to Corregidor Island...

Corregidor is worth a day trip. Same for Tagaytay and the beaches in Batangas. If you like slightly more rugged, rent a car for a day and drive over to Infanta/Gen Nakar on the east coast, easy roads and interesting scenery, or do the loop around Laguna de Bay.
Nightlife depends on what you like... Makati for the club scene. I think the best live music in the youth/Indie scene is in Quezon City. Go to www.clickthecity.com and browse a bit, lots there...
1 ) hike up MT. Pinatubo 2 to 3 hours north of Manila, leave early and reward yourself by doing some barhopping on Field's Ave in Dau before going back to Manila. I drove up and parked at the end of a provincial road / dirt path but it might be a good idea to book a daytour from one of several tour agents on Field's Ave.
2 )Pagsanjan Waterfalls Take 2+ hour bus to Santa Cruz, Laguna, then a 20 minute jeepney to town, arrange a dugout canoe with 2 boatmen to take you up the 6 or 7 rapids for 2 to 3 hours for P500 to where you can swim under the falls. Good time to go Sunday thru Thursday with less group tour buses. But don't let the aggressiveness of the loaals to spoil your trip; they're only human and the group tours have spoiled them with OVERpaying.
3) TAAL VOLCANO in the middle and overlooking Lake TAAL, take a bus to Talisay 2 hours and a banca across the lake. Definitely take the small horses option rather than hiking in what will be ankle deep mud trails in raniny season or miniature dust clouds during dryer times. BUT walk at least 500 meters doing mulitple rejections of renting the horse ( size of a pony ) saying "mahal" "Mahal" meaning expensive added by "tawad" meaning discount and pay about P300 or MAX P500.
4 ) Corregidor Island is okay but personally I wouldn't have spent the money. But my Dad paid since he's into a veteran and war history buff etc
Or if it's raining as much as is has been from Sept. 12 to Oct. 7, 2007 do as Manilans who can afford to would do go hang out in the various shopping malls, each with their own particular ambiance and clientel, check out the cinemas for good films, pamper yourself by getting a facial, hot oil, manicure, pedicure and various types of massages, try out some of the great variety of restaurants and maybe hook up with a pleasant companion have your meals delivered until it's time to depart or it stops raining long enough to go to the places I mentioned above.

hey there! why not check out <a href=http://i-gotta-go.blogspot.com/search/label/viaje%20del%20sol>viaje del sol</a>, it's a group of attractions just 1.5 hours away from manila. :) you can ride a raft on lake pandin, enjoy the quaint charm of casa san pablo, enjoy gourmet meals in kinabuhayan cafe, or check out ugu bigyan's masterpieces.