I've just done something like this in my new build.
Using an Intel 520 Series SSD 180GB and making use of an existing Samsung SpinPoint F3 500GB.
You can either choose to install OS, Apps etc on the SSD and use the HDD for less speed critical files and / or backup storage.
or
If your chipset supports Intel Rapid Storage Technology, which I think is Z68 & Z77;
Use up to 64GB of an SSD (change to SATA controller in the bios to RAID is required), install Windows with Intel Rapid Storage Technology drivers (RAID drivers). Then in Windows install the Intel RST App which then allows you to use the SSD as a cache and will create the up to 64GB partition on it. If you use a bigger SSD the rest of the space left over on it will be left as unallocated space for you to create additional partition(s). Probably just one or two to use up the rest of the SSD space, I've done two as I'm also using Intel Rapid Start Technology to dump a hibernation file to a separate partition which gives me 5 second wake up the PC back to where I left off. This Rapid Start I think also gives me some power outage protection if that occurs whilst the PC has hibernated. The SSD cache creation process will ask you which HDD you want to accelerate and that will be the one it stores the most frequently used files from, into the SSD cache. The advantage is that it's simple to manage as you continue installing almost everything to your normal HDD C: drive and the SSD cache will change dynamically based on your usage. It's also very cost effective if you want to limit your SSD expense to something like a 64GB or less, model. If you use a larger SSD you can use the remaining space for fraps type recording or cherry picking important files or applications you definitely want placed on the SSD. The downside is that the cache won't be as quick as using the first option to install what you can fit onto the SSD but will still be significantly faster than HDD. It depends on your usage, many files on the OS for instance are often used without you realising so these will be served fast from the SSD cache. Other files and Apps you use less frequently may not be stored in the cache if the cache is full with more frequently used stuff.
The third option is buying multiple SSD's and configuring them in RAID 0. Not necessarily much more expensive depending of course on deals available. Instead of sinking whatever you've budgeted for a 512GB for example, consider two 256GB drives instead. Also if one should fail you've only lost half your investment if it happens outside of warranty. This third option should give the best performance of all and Intel are starting to support TRIM now in RAID subject to having appropriate chipset, appropriate RAID add on ROM, appropriate Intel RST drivers, Windows 7, although it is meant to be in the works for W8 too.
I can't recall how fast my new build was when using the first option above but with things currently set up using part of the SSD as a cache I boot into W8RP from pressing the power on switch to being at the desktop in around 20 seconds. I'm making more use of allowing the system to hibernate though and getting back from hibernation in 5 seconds which is faster than the first option would boot from cold. I know that isn't a like for like comparison with that last sentence but if you don't always need to do a full shut down then the wait for a cold boot is less relevant to real world use.
The Sammy 830's look a good deal at the moment with the extra cash back offer and I think the Vertex 4's, Intel 520's are worth considering also in terms of performance but also the longer 5 year warranty.
I've changed the example in option 3 as some of the smaller models in a particular range don't share the same performance as larger models.
e.g. Sammy 830 128GB state a lower write performance than the 256GB model, however the same is not true between the 256GB & 512GB so two 256GB should be better than two 128GB models performance wise.
