If you want managable and fun, I highly recommend a Honda C90.
Absolutely amazing fun, cheap and servicable!
http://www.autotrader.co.uk/classif...-type/featured-listing/dealer/19710/usedbikes
The ER6 range of bikes are ideal for new riders, but depending on how much you ride and your ability - you might outgrow it or get bored. They are still great all round bikes, though.
If the newere CBR600F bikes are as good as the old - that may be a good compromise between being user friendly and having that extra zing for when you become more confident.
They used to be all day comfortable too -but I'm not sure on the new ones. Have not ridden one myself.
Build quality of Hondas are renowned, but the new 600F is reportedly built in Italy, not Japan. That said I have read somewhere that the engines are shipped over from Japan, so reliability should be the same.
The big thing you need to consider is insurance. A 600F is going to slaughter you, both because you are a new rider, and because it is a relatively new model, so insurance companies will hedge their premiums a little higher too. Theres a guy who commented on the MCN review who is 35, and it cost him £1050 to insure the 600F (had his bike licence 9 months). Everyones circumstances are different though, but I would definitely get quotes
before you buy!
If you are adamant on a naked, the Street Triple is a corking bike, but I found it to be a little too small for me. I found it had a very compact riding position, but it was great fun to ride. Also, being a triple it sounds lovely and has good all round power delivery.
I have also read good things about the new shape Honda Hornet, but I have never been on one personally.
Right - generally any 4 cylinder bike will be a lot more revvy. Particualrly in the 600 class where they dont tend to have much torque at lower revs so tend to feel a bit flat. A lot of sports 600's are high revving and produce their power high in the rev range. You may read references to top end kick - that is where the power band is at its sweetest. Generally though, you need to keep them on the boil to get the best out of them. That said, they will be ok at lower revs, just you will probably have to knock it down a cog or two to if you are planning any kind of overtake. I also found engine braking to be far less severe on a 4 cylinder machine, unless I was high in the revs.
V-twins are very punchy low down - think of them as the equivalent of a diesel engine. They tend to have far more torque lower in the revs and will pull like a train - as well as sounding ever so sexy! However, they tend to produce their peak power at far lower revs, meaning they 'run out of steam' as it were. My Shiver 750 was a fantastic bike up to about a ton/ton ten where the drive petered out. That is because although it was a 750, it only generated around 75 BHP. I think it topped out at around 120 as I remember, if the road was long enough. Generally a V will have more engine braking, but engine braking depends on so many things - bore, stroke, RPM etc etc. Generally though, V's have a longer stroke, so tend to offer more engine braking.
Parallel twins are just half of an inline 4. They are a strange one - still quite punchy low down but not as much as a V, but generally rev harder and dont run out of steam as quickly as a V. They have a reputation for being vibey as well. They are also a bit smoother on power delivery than a V. They tend to produce their peak power a little higher in the revs than a V, but lower in the revs than a 4 cylinder.
Personally I have owned and ridden all 3 types of bike, and the v-twin was a hoot. I loved that raw, low down grunt that tried to dislocate your arms.
That said - a sporty 600 on the boil is also very exciting. It kind of feels like warp factor when you get into the sweet spot, but due to the high revs they aint the best to ride at speed for any length of time (noise and buzz etc).
If I am honest though, I miss the four cylinder Japanese fun! If I have another bike, I think it is going to be a Blade. There is just something about that kick up the backside at higher revs and the way the scenery starts whipping past.
You will find the different engines different to ride, no doubt about that. I find twins far easier to ride as you dont have to always be in the right gear. That tends to make you lazy as you can bumble on through the corners without needing to change. A sporty 600 is a different story. You need to think a lot more about your gears and your speed/revs when cornering. If you ride a 600 in a spirited way - you will need to keep it on the boil - the problem with that is the throttle response so high up can be very acute, and the bike can start feeling a bit skittish. I personally find four cylinder 600's far harder to ride smoothly and rapidly than a twin. Lots more thought required, and a lot more gear changes. In fact, so much so it can start to become a chore.
But overall, all 3 types of engine can be immense fun