Welcome back to the world of Blood Bowl
It sounds like a fairly mixed league (Chaos - bashy, Elves - dodgy, Halflings - stunty, Nuns... are they being played as Humans, Amazons or something else?) so Humans and Orcs should be competitive in that environment. Humans and Orcs also come with handy reference sheets
Two questions to ask yourself are "Do I like the miniatures?" and "Do I like the background?". This is especially true if you haven't worked out what style of play suits you best. It is important to get a team that you genuinely like for some reason. If you don't you may have problems motivating yourself to get those players painted.
Remember that there are other manufacturers with great miniatures out there (as your league demonstrates with the Nun team). Take a look at Shadowforge and Neomics amongst others for alternative miniatures that are competitively priced and might appeal to you more. Both Neil at Shadowforge and Jens at Neomics are quite friendly and offer excellent service. Goblinforge also has some great alternative players (but no complete teams yet).
Humans and Orcs are recommended for several reasons -
1) They come with the box set. You don't need to spend any more money unless you want to, which can be an important consideration.
2) With time, you can make either of those teams into what you want - running team, pass oriented team, bashy team... you name it and with patience you can turn them into something to suit you.
3) They are generally forgiving. As they are not oriented towards any one task, Humans and Orcs don't do anything really poorly (or exceptionally well on the other side of the coin). You can make mistakes and still have the strength, movement, agility or whatever to dig yourself out of that hole. It doesn't what you do with Khemri, for example, they just won't pass, dodge or move well.
If neither of those teams truly lights your candle, by all means look to another.
Dwarves are not all that slow despite their stunty little legs and can hold their own.
Elves are problematic for me to recommend to a beginning or returning player in a league environment. The rosters that you would be able to afford from the start tend to read 'lineman, lineman, lineman...' which is great for spreading those skills around but you will keep staring at the more characterful players and think that though this is fun that you really want to be playing with those cool guys that were left in the box.
Skaven offer a good deal of movement and decent agility but at the expense of armour and strength.
Norse and Amazons are both variations on the Human team but as they start with block and dodge respectively, they have a starting leg up which fades as the other teams in the league get skills to counter their advantages.
And the list goes on... Look around the site as there are 'how to' guides for most teams (skills, starting rosters, etc). For painting inspiration, look at
http://www.bloodbowl.org which shows some lovely painted and converted teams.
I guess, just avoid the more difficult teams like Vampires (When they work, they work. Otherwise they really can suck - literally and figuratively) and remember to have a good time.
Helping other players' rankings since 2004...
