[TZENU]

Good luck with it.... Cycling is very addictive!

Within the first 3 months of cycling on trails with a hybrid, I upgraded to a cheap road bike (Giant OCR 3) and that alone made an awesome difference in cadence and speed..

If you prefer to go the road bike I route I would personally begin with looking at an alloy frame bike with 105 gearing (some might argue with this but I find it is a nice compromise between comfort and speed), which will last many years of cycling and won't hit the hip pocket as hard as a carbon fibre bike.
As has been mentioned a proper bike fit is essential if you plan on clocking up the Kms to avoid injury. (I had developed a knee problem and was advised to get properly fitted. Since that day I have never had any problems)
From there you can teach yourself how the gear's work and which gears are best suited for the areas you ride.. and aim to keep your cadence in the 90 range.

I started off on a Giant OCR 3 which all up incl accessories set me back about $1k... I rode that for 2 years and clocked up around 8,000km
The bug had bitten so I upgraded to a Bianchi 1885 with a veloce gearset and some Kysirium wheels, rode that for 6 years and was a dream to ride in comparison to the OCR 3.
Earlier this year, I acquired by first carbon fibre bike a 2012 Ridley Helium (Vacansoleil team).. This thing to me, is the bees knees and only weighs 7kg with wheels, pedals, stem and handlebars and hopefully next year will start competing in some crits.

If you asked me what I thought about cycling 10 years ago, I would have laughed at you and told you that if you wanted to lose weight, start running... Since starting I have lost a decent amount of weight, but have also gained a lot more power in my legs, which I would never have had if all I did was run!

Stick it out and you'll be rewarded and there is no doubting that!!

O/T V.Nice Merckx gecko!!