We are doing ala carte for ours too.
Banquet wise, we just went to a wedding fair at Marina Square atrium (in 2007) where several hotels have set up booths and we picked one which we think is the best value for our bucks. Prior to signing up, we have spoken to friends and visited those hotels which were recommended by them. Next, we set aside a day to check out their ballroom venues and speak to the wedding coordinators. I think it is pretty important that you choose a good coordinator as problems might just crop up and you might need their help at the last minute. Remember to call the wedding coordinators beforehand, otherwise it might be a wasted trip for you. Most of my friends will pick a hotel based on the 1)food reputation, 2)location of the hotel and 3)general reputation (how many stars etc).
We are doing ROM and banquet seperately. ROM wise, we both want it to be very simple. Sign the papers follow by a simple buffet at a hotel. I am not buying any ROM dress nor thinking of engaging a makeup artist as we both prefer the more natural look. Suit wise, we went to this Dan-Stevenson warehouse sale and bought a 3 piece suit for him, consisting of a blazer, trouser and a vest. Cost : $249. Their quality is decent for that price (we feel). For his ROM shirt, we went to Tangs sale and bought a Caserini shirt for $40. When Tangs is having a sale, we would always go to their gents department to check it out. Other places where you can get the groom's shoes are warehouse sales, there was a recent Pedro warehouse sale and my brother bought a pair of leather shoes for $80 only. Formal leather shoes and at 50% off. Keep your eyes peeled for newspaper ads, sometimes, these are quite good bargains.
I bought my wedding gown from one of the forumers who already had her wedding. The size is kinda off but I would be altering it soon. I find it more economical to buy directly from the sellers and also more environmentally friendly as we are 'recycling' it since wedding gowns are hardly well worn.
We are thinking of getting the flowers (for the car and bouquet) from wet market florists. Alot cheaper for something which is only suppose to last for a day and I do not mind personally.
We asked one of his friend to be our ROM photographer and we intend to give him a big ang pao. Actual day wise, we have not sourced for the photographer yet. We do not know if we are going to get indoor photoshot yet.
We are quite a cost conscious couple hence, we took a longer time to plan for our wedding. ROM wise, we took like 3months, as we are not doing it at ROM centre and had to source for JP and a suitable venue. We failed to secure a slot on our preferred date at ROM centre otherwise it would have been cheaper. However, I would advise you to hold your ROM and banquet on the same day as there would be less to plan for ROM (since you both are not planning to buy a house yet). Some friends have even held their soleminsation during the banquet whilst others held it 1 hour before the banquet starts. Depends on what you both are comfortable with.
Hope the above helps.