I have an AMD and an Intel system
PII 965 BE (790FX chips) and i7 930 (X58 chips)
Same cards were used (2x5770s).
Now, lets remove synthetic benchmarks and get into real world gaming.
Most games load noticeably faster with the AMD, but that is is where everything stops. Playing F1 2010 i see the biggest difference between the two systems. The AMD drops to 45-50 FPS low and max of 65-70 FPS (1920x1080 maxed out 8xaa and ultra settings). Mind you, that is with the system screaming and shouting at 4.1Ghz CPU, 2.8Ghz NB and 2.6Gh HTT
Stock intel I7 930, same game and settings, i see lows of 60 FPS and highs of 82 FPS.....that says a lot, imagine overclocking that 2.8Ghz to 4.1Ghz to match AMD speeds.......
However, i was and still am more than happy with my AMD system, the Intel feels a bit overkill, but is does prove itself as mentioned above, a nice boost comes with the extra money.
The Intel system costs in the €200-€250 more than the AMD system (mostly due to more expensive ram, expensive board and CPU). But you do NOT need an X58 board with a €300+ price, a nice €200-€250 will do it just fine, placing the boards in the same league as AMDs top 890FX boards.
However, personally, i prefer more physical cores than threads. So if i were you i would go for the 1090T BE and a 890FX board and a Noctua CPU cooler and overclock that into a monster, but ONLY if you plan to stick with AMD video cards. if you plan on using NVIDIA, youre locked into using Intel.