212 EVO used to get me to 4GHz and under 60 degrees at load on my Phenom II for the grand total of £25
Its got an Arctic Cooling Freezer 7 on it now that only gets to about 3.8GHz with good temps this one cost me about £18 I think.
The cheaper closed loop watercoolers wont really get you any better than the 212, unless you splash out alot of cash on a custom loop but even then your going to hit a ceiling on the overclock that means the loop probably wasn't worth it.
I'd stick with air unless there is another reason to go liquid (aesthetics etc)
Theres a few reviews and comparisons of a H80 its about the minimum you need to start outperforming even cheapish air coolers. Aesthetically they clearly are a winner though if you have a side window and dont want a big old heatsink or of your RAM has tall fins so cant fit a big HSF just performance wise its hard to justify spending triple or more to get a very small performance increase.
Which Phenom do you have? If it's a 955/965 you can often get to 980 speeds (3.7GHz) on the stock HSF with just some multiplier increases. To get the big OC's though you will end up OC'ing the NB and fiddling with voltages too.
i have a t-bird 777 case which has a side window, phenom ii x4 850 with the l3 cache,
asrock n68-vs3 fx motherboard, 4gb ddr3 1033, 500 watt psu, 500 seagate pipeline hdd with cooler, asus 4350 graphics card, samsung dvd rw, 1x chasis fan
well im happy with my board can take the 8 core, will get up to that, will get 8gb corsair vengeance a better graphics card as this ones crap but i aint a gamer i have a ps3, a new ssd drive, new psu and a new cooler, but liking the look of the asrock extreme motherboard, gorgeous