My current bike's a Merida Crossway and a mate has a Merida roadie. Neither of us have had any issues with them. Rode mine today, it was great.
For a saddle, get a gel one for comfort. I can't remember the make of mine at the moment but I bought it for my previous bike and have since shifted it to my new one. So much better than the standard seats. Don't get one that looks like **** off ebay, get one that looks well made. Or get one from the bike shop so you can try it out first, etc.
For wheels you want 26" or 700cc. Bigger wheels means less rolling resistance means an easier ride. Those are also the easier ones to get replacement tubes and tires for, should you need them.
You'll also want a helmet. One that fits well and is easily adjustable.
Depending on how busy the roads are where you're planning to ride you might also want some kind of loud horn to blow at cars/stupid people. Most bikes still come with a bell but they're completely useless for anything serious.
If you want to ride at sunrise/sunset or evening a reflective vest and head and tail lights should be on the list.
If you don't already have a pump there's some really nice floorstand style pumps you can get now with a pressure gauge on them and stuff. Useful to make sure you keep the tires at the right pressure, which helps with rolling resistance, grip and preventing punctures and such.
And you might want a puncture kit. Just in case.
Blackman Bicycles have a shop in Parramatta, suggest you wander in there some day and have a look around. I got my bike from a Blackman's shop and they were super helpful. And gave me a good deal, too.
"Wasabi is a sometimes food." - Elmo