well this new one has 4 pci, 1 pci-e 1x and 2 pci-e 16x. it would work fine for your purposes. it's an Intel 1156 socket mobo so you can save some money and get an I-5 instead of the I-7 based cpus. Newegg.com - GIGABYTE GA-P55-UD3R LGA 1156 Intel P55 ATX Intel Motherboard - Intel Motherboards
and yes it only has 1 1x pci-e slot you are going to say, but the beauty of pci-e is if you have a higher x number slot you can put a lower one in that slot. for instance you can use a 4x pci-e card in an 8x or 16x slot and you can use a 1x card in ANY pci-e slot. as far as 4 pci slots in a new mobo you are looking at expensive high end boards or workstation boards with pci and pci-x mixed in with pci-e or overpriced crap from yesteryear like a pentium 3 board etc...
as far as the issues you had with that 7xx series nvidia chipset it is probably due to a combination of factors not a single one. some kind of incompatibility with a component in your system and an unstable set up. turn cool 'n quiet off in the bios entirely and never ever ever turn it on again. put only the minimum hardware neccesary to boot into an operating system and get video and network going and update drivers for what you have going at that point. then add the next most important hardware and see how it goes. in your case...
put in the hard drive, the dvd-drive, the vid card and the ram (2 sticks only) and cpu. plug it all in to the power supply and mobo and boot up windows. load drivers and update as neccesary. then add in your uad cards starting with pci one at a time with a reboot inbetween and a test as well inbetween. then go for the pci-e cards if all is well and see how that goes.
also make sure that cool 'n quiet is off in the bios as well as these peripherals / features disabled...
(if not using ide drives and all is sata) turn off the ide controllers
turn off the printer port
turn off the serial ports (not to be confused with the usb ports)
turn off floppy controller
turn off onboard audio
turn off onboard firewire (if you do not have any audio interface that's firewire or have a dedicated firewire card you'd rather use)
turn off usb keyboard/mouse emulation
things to make sure are enabled or turned on in bios...
usb 2.0 (sometimes called something different in bios but basically high speed usb should be on)
built in network controller should be on and if settings for speed exist set to highest speed card supports such as gigabit or full duplex 100 etc..
make sure sata controllers are set properly for your usage i.e. if you are going to use the drives individually and not put them in raid 1 or 0 or 5 or 6 make sure the controller is in ide mode or sata or basically anything that isn't ahci or raid mode. if you are going to do raid set it up at the beginning before you install the operating system and create the array and then install to it only if you are doing a raid array for the operating system's drive. other wise if you are doing a single drive off the raid controller for a boot/operating system drive install all the drives and set the ones other than the boot drive in raid arrays first, and just leave them unpartitioned or un-used until you get everything going first.