Thanks Ellert for that post. Looking forward to more from you. I am still not sure what colour I want to collect yet, but will try Black, maybe white and Red since I just got a deck with Dragons vs Knights.
From what I seen so far, Green Land cards, some of them have extra abilites, that so far I haven't seen from others. Is this unique to Greens then?
I haven't seen a Deck Builders Toolkit yet, but I will keep my eyes out for them. Thanks Orzorn for the links I am checking them out now.
White and Red could be fun, red is a very aggressive way to play, it often encourages you to destroy your own creatures for the sake of dealing damage, for example with Flinghttp://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=241858 and http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=220435, however that doesn't mean it's bad. Take the aforementioned Goblin Grenade and use to to sacrifice a creature called http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=242485, a creature that deals one damage to either a creature or player when it dies and costs only one mana. Then you're left with dealing at least 6 damage to the opponent for only two mana, even more if you manage to attack and he lets the attack through since you can play Goblin Grenade at any time, so you attack and your opponent decides if he want to block the 1 damage or not and if he does you can still play Goblin Grenade and deal 6 damage to the opponent even if you don't get that 1 extra damage from the initial attack through.
You'll see that this kind of playstyle leaves your own field quite empty of creatures but white is excellent at allowing you to survive and it can have enchants that offer you even more damage early on.
There is more to white and red but I'm not gonna delve too deeply into that while I don't even really know what kind of playstyle you may end up with

About mana, it was mentioned that you should go for 15-20 lands but it is generally recommended to go for around 20-24 lands, wizards of the coast design most all of their starter decks with 20-24 lands and they recommend a balance of 2/5th lands (24/60), 2/5th creatures (again 24/60) and 1/5th(12/60) of other spells such as instants and sorcery.
It's not an absolute and I myself have quite a bit less creatures and more instants and sorcery keeping them nearly equal (I got a bit more creatures) and I have 22 mana in my deck, 4 plains, 16 forests and 2 special lands called http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=221923 (it gives me either white or green mana if I tap it, the choice is mine).
Some would say I have too few plains but I keep cards to find them such as http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=233231, http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=249399, http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=236907 and sometimes I even find myself searching for a plain through a creature called http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=241832, however it's rare that I don't have a plain out by the time I can cast that card even if I only have 6 lands that give me white mana (the 4 plains and the 2 sunpetal groves).
So you can have too little of some mana if you have enough of ways to acquire it, my mana searching tools can all use green mana so I mostly use green mana and then just keep a few planes around in my deck for a few white cards.
Sunpetal grove is also just one of many special lands and they are not bound to any color, you can use a special land in most any deck if it's of use to you.
About playing as black that is entirely possible and playing mono (single colour) can even be better as a beginner because it's easier to work with mono decks. My friend runs a mono black deck and can beat my deck just as easily as I can beat his deck, so it's viable but I personally don't find mono decks to be all that fun, there is a certain flavor that is added to the game when you mix two colors or even more together, however the general rule of thumb is that the more different kinds of colours you keep in your deck the harder it is to build it properly and if you carelessly throw all the colours in a single deck you may find yourself starved for certain kinds of mana you may need.