We have a 90cm gas cooktop and a 60cm electric double wall oven (the upper one being standard size while the lower one is two-thirds of a full oven). We have two deep drawers under the cooktop in which we store all our pots and pans. But our beach house has a 90cm Ilve upright stove - gas cooktop and a single 90cm oven. So having both versions, while I love the Ilve for its quality, I have to say I find the separate cooktop and wall oven works better for me. No bending over to glance in the oven or to take hot pans out. If you have the space, I'd seriously suggest you look at wall ovens. Here in Melbourne, Camberwell Electrics will let you try out their appliances by cooking a meal. (A friend was looking at a new oven and they let her cook identical meals in both a steam oven and a standard convection oven so she could compare the two. It certainly won them her business and solved her dilemma too.) Maybe a store near you will let you try out the different ovens for yourself?

apart from heat issues (check with manufacturers for a definite answer ) i prefer to have the appliances separated for ease of access and to have a set down space nearby

We have a zip built into our ceasar stone bench top next to our sink. We opted for the font (the mesh waste) and riser (it attaches to the bottom of the zip to give it extra height) We have instant boiling water (you can only use it when you press the safety switch located under the boiling water switch) chilled filted water and sparkling water. The sparkling water is sensational. We worked out the ratio and it is of equal value (replacing the canister as to buying X amount of bottles of mineral water over the same period) and we drink a lot of it (we are a family of 5) The unit itself sits under the sink and is smaller than a case of beer, and next to it is a C02 canister (resembling a small tube) We now don't have any empty water bottles in our fridge or cupboards, we no longer have a shelf full of mineral water (the filter water is so pure and clean) and I don't have a kettle on display day and night!! Yes the initial outlay is expensive but it looks fantastic is easy to use and I would highly recommend it.

Thanks everyone for your comments so far. Some great points have been made and I'm going to take each one of the away to have a think about. In the meantime, I've asked my draftsman to provide me all the measurements to existing and proposed so I can share it here as soon as I get them. Some more info: We're located in the northern suburbs of Melbourne. Our budget is approximately around the $200k...this is so we don't over capitalise on the property. We thought about building to one boundary because we are of the thinking that we need more width to achieve the space we want. As a guesstimate, I believe the block is 12m or so wide. Each lane way is approximately 1.5m (3m combined) which only leaves us with an internal width of 9m (minus walls). We chose to explore building to the eastern boundary because existing utilities such as hot water system, ducted heating are already setup there. Moving it to the western boundary would cost $$. The eastern laneway has nice new concrete paving and allows us to more easily access it from our carport.The other reason for potentially building to the east is because we're the 2nd last house on the street (near a corner). We get a bit of traffic on our street but more so on the street parallel the western wall. I thought it would be more peaceful moving the house away from the traffic and noise rather than towards it. Also, the addition of the dining area (connected to kitchen and alfresco) will give us a bit more privacy from the street (parallel to western wall) when we're out on the alfresco/deck. Just my thinking but happy to get some further feedback. We're happy to consider keeping the current building boundary if we can achieve the design we want etc. I've attached a few pictures of the existing low ceilings towards the back of the house. The pics show the ceiling from kitchen and towards the back door (curtains are closed). The ceiling is about 2.4m and you can see the exposed beams which makes the ceiling feel even lower. I'm only 1.6m and I can touch them with my finger tips if I try... Whether it's a full knock down or increasing the height of the roof, I think it's the one thing we're about improving/removing. Hope that's some more info for everyone to go off... Thanks again for everyone who has already replied and made some great points. Cheers