I really liked Penang and in particular Georgetown. It's a shabby chic kind of place with tons of history and great food to boot. We stayed 5 days ( slightly longer than anticipated due to Bangkok airport being closed) but actually that was fine as we were able to take it slow. We would consider going back for sure.
I also LOVED the Bon Ton resort on Langkawi and whilst Langkwai didn't blow me away theBon Ton did and again we would most definitely return for a chill out and some amazing food.
KL I don't really care for and for me a couple of days is sufficient. We did a half day city tour which was good and also went out to see the Batu caves ( not to be repeated)

In my opinion, KL is a big city and not very interesting as a tourist destination. I go at least twice a year for business. It's worth going to to see the Petronis Tower, maybe go to the KL tower and enjoy dinner while the city spins beneath you. I stay at the JW Marriott, which is adjacent to a huge shopping mall with all the expensive shops.

Penang is really worth visiting as is Melaka. I agree with what Smeagol said about Penang/Georgetown. I stayed at the Shangri-La resort outside of Georgetown which was very relaxing.

Have spent time on Langkawi at the Berjaya resort. Loved it. If you go, take an island hopping tour.

I was in Malyasia on some business back in the 80's and found the people very kind and friendly. KL is a monstrosity with isolated pockets of pleasantry, and it has it's attributes. Melaka is quite different due to its Dutch influence...and the Cameron highlands are not to be missed...for a cool weekend out of the humidity down below. Can't recall the name of the resort where I once stayed.

I always stayed at the Equatorial Hotel, across from the Shangri-La, mainly because my client's family owned it..and that's where they put me up...always giving me the penthouse suite. The first time I was there, the entire family met me at the airport, kids and all, and all congregated back at the penthouse suite, with the kids raiding the mini-bar to the last cookie and candy bar. Penang did't please me nor did Georgetown, so I kept the visits short.
Would I go back as a tourist? Probably not.

georgetown penang is wonderful... see if you can get into clove hall (upstairs front rooms) or the E&O (kathie's fav).
placve is good for perhaps 3 full days.. great restaurants there

K/L is boring, boring... the petrasos (sp) tower tour is really the only thing we found worthwhile, and maybe one marketplace.. 2 full days max... richard deserves a better place..

langkawi is another malay place which is nice for a bit of a rest...

sheraton or bon ton hotel..

btw, sheraton imperial in K/L is very nice and next to the rapid transit..

I find KL kind of boring (sorry). Fine for a couple of days.

We loved Georgetown Penang and spent a week there. We also loved Malaysian Borneo - both Sabah and Sarawak.

I'd fly from Bangkok to KL - it's about an hour. Or, fly directly to Penang. There is a Thai Air non-stop BKK to Penang.

Yup, Georgetown Penang is worth some time as is Bon Ton on Langkawi. Our trip report from last July is here:
http://www.fodors.com/community/asia/craig-jeanes-2011-official-trip-report-malaysia-and-singapore.cfm

I would largely agree with much that has been said. I visited KL once or twice a year on business for the past ten years, and also thought it interesting, but no big deal. However, in the last couple of years, I've begun to find that there's more there than meets the eye. I was talking to another travel writing friend recently, and we both had the same feeling about the place.

The challenge to KL is that it's so spread out, and while there's a big network of trains and the monorail, they don't necessarily go to all the tourist places. The hop-on hop-off tourist bus can be a really good option for getting to places like the national museum, bird park, Brickfields, etc. The bus was one of the factors in my realization that I hadn't really seen all that KL has to offer.

Another place that hasn't been mentioned is Melaka, less than two hours' drive from KL. It's easy to lump it in as a place just like Penang, but it isn't. It has a much longer history, and some really interesting museums (more than 20 of them in all).

If you're coming from Bangkok, I would definitely fly to KL, although if you really want to do Penang, you could fly there and then hop your way down to KL, maybe stopping in Ipoh or Pangkor or Cameron Highlands on the way. I like the Malaysian 'VIP' buses and have no qualms about taking them anywhere, although my limit for any bus trip is about 4 to 5 hours.

we spent several days in meleka, and while we enjoyed it ok, we did not love it like georgetown

Thank you, All! The way things are going now KL is off the itinerary ~~ maybe forever.

Bob, you are right ~~ R does deserve better. Khao Lak this year!!!!!!!

Sandra

Here is my trip report We enjoyed our stay immensely. I hope some of the info can help you make a decision

http://www.fodors.com/community/asia/backm-from-singapore-kl-melaka-and-penang.cfm

Sandra, you will LOVE Khao Lak. The JW is fabulous. Get one of the pool access rooms. You won't regret it. I had the room next to B and K and it was right along the canal. You step directly into the water from your terrace. Wish I was there right now (even though I'm not a swimming person at all).

......but I still want to 'do' Penang at some point.

sad to say the JW currently has prices twice the amount i got our res for back in jan for the nov timeframe... same thing happened last year---the early bird...

but worth it at any price!!

I think KL city with a taxi driver for 4-5 hours is sworth a day, I also think if you woukd devote 2 days a trip to the Cameron Higghlands is simply magnificant. The Sheraton -Luxury collection is surprisingly elegant and exceeds the Rights Charton and others by far and is 25% less expensive. If you dive or snorkel 4 days in the Redang Islands is excellent underwater conditions mid0Marcgh to July. It is a 75-80 minute plane ride fro KL's domestic airport. I would add 4-5 days in Penang and yould have a lovely 2 week trip.