I'm a 2nd level Barbarian and can train Push to 100... is it worth having above 40? (which is what I have it trained to now) I'm assuming this becomes an obsolete skill higher up, same for Bash and Kick? Thoughts?

Well, a few things to remember:
Your background gives a bonus to some of these skills. Go by the percentage in 'show skills'.
Those skills do more damage at higher percentages.
Yes, they will be obsoleted later on, however...they are also very cheap skills, so in the big picture, the experience you spend is a drop in the bucket...by the time you have access to better skills, the amount "wasted" in push/kick/bash will be so trivial you won't notice it.
Many people reinc when they finally get the exp to max their guild...when you do that, you'll recover the exp spent in those skills as well.
Bash has an effect that is (rarely, but sometimes) used at higher levels -- it has a chance to break a monster's concentration on skills/spells. In some rare cases, the party will ask the tanks to bash the monster you're fighting.

In short, I wouldn't save up to boost those skills, however 70% or so is usually pretty cheap, and may help you gain experience faster. Also, if you think you'll reinc later (you _will_ reinc later), then those skills are also a good place to "store" experience -- they are cheap, so you can train off that last bit of experience before doing some dangerous explore runs, etc.

--ooga

Ah, thanks much! Very helpful! :)

I would agree with Ooga, train to 70-80 as it is still quite cheap and much better than 40.

Most newbie tank skills already are quite useful at low % like 70 and they are still quite cheap. So generally I would try to get every useful skill to 70 and then start to train to 90. As newbie be especially careful with the 90->100 training as those percents are exponentially more expensive than the lower ones.

And also notice the background bonus, so for nomad skills like attack are much easier to get to 100 as you actually need to train only 70% and the expensive last 30% comes from bg bonus.

And some skills do work better over 100, some do not but as a newbie this is not really important. (The lvl 31 dwarf ranger with 112% attack was not a good move)