i don't buy monks though, i tend towards items only. do you think monks would be worth it in a pent build, i never tried it
absolutely worth it, regardless of your build. Idol priests, now that HoL is an artifact, are the best health regen in game without a doubt, especially for the price. I'll usually skip over l2 and l3 unless stacking with an ally or playing with a Sedna. Bishops at 2700g are a steal and easily achievable by level 5, and they give you and your allies a decisive advantage if your opponents don't match them.
shield lev 1 is necessary if you are playing hyper agressive or savior.. Anything else and its silly.
Maybe it's my "aggressive savior" playstyle, then, but I can't really imagine building an Oak without that early point in shield 
Ke5trel, want to give tips on early game shield usage? Particularly for initial encounters?
It's kinda hard to set down rules for this one - the cd is so long that if you use it early you will waste it, but if you wait too long you or your ally will die.
Broadly
1. Use it to purge, but only when your opponent has commited to battle - if they are, for example, playing a spit harrassment UB don't waste it on purging the spit until UB is coming in for a sustained fight. Worth noting that debuffs will penetrate shield if they proc after shield goes up - so if you shield and then UB spits when you shield is gone you will take damage on the remainder of the spit timer. This is most important when fighting any team with a slow reg or ice tb..
2. Use it to block nukes - it's part of what makes Oak so great against Slam Rooks and Snipe Regs, but if you keep track of opponent cd you can negate a bunch of instant nukes like Sedna's pounce too.
3. Use it to make a tank - it doesn't matter who you cast it on, for 3-6 seconds they are invulnerable - this makes them a tank. If you have three enemies piling on one ally you can shield him just to keep him in the battle or shift the focus to a stronger ally. It's difficult for most opponents to shift their focus once committed, so you can really change the flow of battle just by negating the damage early
4, Use it to escape or help your allies escape. The purge and the invuln mean that you can stretch point of no return way past most other dgs. You can pursue an enemy past two sets of towers at level 4 and get out, more importantly, you can stay safe and warm and use the incredible range to get your ally out.
A good shield oak is going to cut down on team deaths as much as a good Sedna or QoT, if not more, but the Oak can also push, farm, and kill more effectively than either, imo...
I'm sure there's more, but that's all I can think of offhand...how else do you guys use shield?
Incidentally countering a good Oak/Sedna team 2v2 is difficult, because they have nukes *and* mutual damage mitigation. In my experience this is the hardest team to beat in a 2v2.
