Hi OP - I've joined Mumsnet so I can reply to your post!
My situation was similar to yours: my husband and I hadn't had any dogs as grown-ups, but we had them when we were children in the 70s and 80s. Obviously we weren't involved in any training or care then, and training methods have moved on somewhat since the 1970s!
We decided on a puppy, who we got at 8 weeks. She's now 11 months old and she's beautifully behaved and well trained. We are very proud of the job we've done with her as first-time dog owners. She's an absolute joy and makes us laugh every single day. So I just wanted to join Mumsnet and post to say to you that it's not an impossible task for a first-time dog owner to do a good job!
We were both dog lovers and had wanted a dog for years, but not having owned a dog before, we were clueless at first. But you have to start somewhere and we approached it by doing as much research as possible before we got a dog, as you are.
We read the following books before we got our dog: Perfect Puppy by Gwen Bailey, It's me or the Dog by Victoria Stilwell, and Total Recall by Pippa Mattinson. I'd especially recommend the last book because having a dog with a really good recall will make your walks much more pleasurable. These are all positive reinforcement training methods.
We also made sure we had good dog care in place before we got her. We both work full time, but I'm lucky enough to work at home. I do have to go into work sometimes for meetings though, so one day a week our dog goes to a fantastic day care we were lucky enough to find. We prefer her going to day care so she gets to spend time with lots of different dogs, rather than leave her on her own in the house. Plus, she's a Velcro dog and doesn't like to be left alone. The most we've left her for is an hour. I've videoed her and although she doesn't show any signs of separation anxiety such as toileting or howling or pacing, she won't touch the treat-filled Kong toys I leave for her until we get back home. So if we want to go somewhere, it's for an hour at the most, otherwise she goes to day care or to my husband's parents who also have a dog.
We were pretty confident we could handle the training, despite being new to it, as we'd read so much, but we also took her to puppy training classes. This was mainly for socialisation and mental stimulation for her. We're also looking into agility classes for when she's old enough - again for mental stimulation. We do training with her every day, reinforcing what she's already learnt and training new stuff as well. We also do dog puzzles with her - have a look at the Nina Ottosson range. We walk her three times a day and we take her to a variety of parks, woodlands and beaches, so she's constantly experiencing new places. We bought her a ton of toys - all good quality tough things with a variety of textures: soft squeaky toys, teething toys, plastic ones, etc. Kong do a good range that are pretty tough. We keep half of her toys in a box and rotate them every few weeks, so she doesn't get bored or matter-of-fact about any of them and she feels like she's regularly getting new things. All this mental stimulation, exercise and variety of toys has meant that we've had no problems at all with destructive behaviour. She hasn't chewed anything of ours at all.
We were prepared for it being hard work having a puppy, but the first couple of months were harder than we thought. There's just so much to do - toilet training, socialisation, separation training, getting them used to different situations and noises, being in the car, loose lead training, and so on. However, if you read those books, you can be fully prepared for all this. And it was totally worth it - she's such a good dog, her recall is fantastic, her behaviour is wonderful and she just gives us so much pleasure, fun and joy.
I'd say the most important things are to make sure the dog is well socialised from the start with other dogs and spend a lot of time on recall training.
Finally, with regards to the poodle crosses - cockapoos, cavapoos, labradoodles, and so on. I actually have one a poodle cross myself. I will say this: she has been a dream to train – she’s so clever - and she's got a lovely temperament; she adores being with humans and meeting people. I'd have another in a heartbeat. (They don't really like being left alone though, so if you do get a cockapoo, I'd seriously consider day care for the days you're at work, rather than a dog walker.) You will find some people have misgivings about these crosses, calling them 'designer dogs'. This is because they are extremely popular - they look very cute and so demand for them is high - and they are deemed to be a fashionable dog. As such, they can be associated with unscrupulous breeders and puppy farms, and therefore have a bad name. (Labradoodles were actually originally bred with good intentions as guide dogs for people with allergies.) Don't be put off getting one of these crosses. Just be aware that they are not a 'breed', they are a cross, and it is important to research both dog types well for potential health problems and also research breeders very carefully.