As for the hotel, my favorite hotel in KL is Prescott Inn ( http://www.kl-hotels.com/prescottinnkl ). You can book online from that website. It's a 3-star hotel so it is cheaper compared to the rests but the location is very convenient. It's near Medan Tuanku monorail station so it's easy for you to go around KL. It is also near SOGO shopping center, Pertama Kompleks shopping center, and Maju Junction Mall. There is Nasi Kandar stall that opens 24 hours in which you can find your typical Padang food there (of course it's not exactly the same like in Padang but it is close enough). My parents love to go to this Nasi Kandar stall. They said the food suits their taste.
My next choice hotel in KL will be Corus hotel (http://www.kl-hotels.com/corus/rates.htm ). This is 4-star hotel and link to KLCC (Petronas towers) and Putra LRT station. If you take Aeroline bus, Corus hotel is the start and final destination in KL to Singapore vice versa. So, when you arrive in KL from Singapore by Aeroline, you can check in immediately into Corus hotel and start everything else from there.
If you are into shopping, you can check out many hotels around Bukit Bintang area ( http://www.kl-hotels.com/accommodation/accommodation4.htm). My choice will be Berjaya times square hotel ( http://www.berjayaresorts.com/timesquarekl/rates.html). This hotel shares the same building as Berjaya times square mall. Berjaya times square mall is my favorite mall. It's big (but not the biggest. the biggest is Midvalley mall) like that mall in BSD tangerang in which you can find roller coaster inside the mall. There is 3D imax cinema in there too. I would love to watch Harry Potter there... :D
Adjacent to Midvalley mega mall there is Cititel and Boulevard hotels. Both are 3-star hotels but Cititel is cheaper than Boulevard. Midvalley has a link to KTM komuter that will bring you to KL Central station. From Central station, you can go anywhere in KL/Malaysia and even check in your luggages if you fly with Malaysia Airlines then take the KLIA express to KLIA airport in 27 minutes only (as compared to 1 hour by taxi/bus). To go around KL is very convenient using its train system(http://www.kiat.net/malaysia/KL/transit.html ). If possible, don't take Taxi in KL because if you don't know the exact price to your destination, the taxi drivers will be happy to give you their price which will be a lot higher than the original price. But in places where you must buy coupon first before you take a taxi, such as KL Central station and Berjaya times square mall taxi stand, you are safe to take taxi from there.
Depending on where you want to go and which places you love to visit, you can decide which one is more convenient for you, book local tour or tour on your own. You can visit this website for reference: http://malaysia.travel/consumer/vmy/default.asp