Replacement for i5-750 Stock CPU Cooler

I have a newly built INTEL Core i5-750 with ASUS P7P55D motherboard mounted in a NZXT GAMMA Mid-Tower Case. I am running Windows 7 64-bit. The PSU is bottom mounted with bottom air intake and rear exhaust. I have a top rear 120 mm case exhaust fan and bottom front 120 mm case intake fan. I am currently running the stock Intel CPU cooler.

I run Seti@home at 100% on all four cores and my CPU temperatures are on the high side now. At a room temperature of about 70° F (21°C) my CPU temperature is in the mid 150° F (high 60° C). Since I don't have air conditioning in my house, summer room temperatures will get into the mid 80° F (30° C), I need to improve my CPU cooling.

I would prefer not to spend a small fortune on an overly complex CPU cooler and so am considering the following options:

Dynatron G950 newegg.com Item#:N82E16835114100
Thermaltake Silent 1156 newegg.com Item#:N82E16835106139
COOLER MASTER Hyper 212 newegg.com Item#:N82E16835103065
Any suggestions would be appreciated.