Go pan for change on the corner and get the xtra ram to go with the 2.3ghz...you can never have enough of both. Period.
Well, the way the prices for CPU and RAM are now it's easy to go 'Stupid Big'. The reality is that single CPU cores have had a hard time creaking way beyond 3 Ghz, and that there is a finite amount of memory programs will consume, and that an OS can use for cache.
On the budget end, I'd certainly want something that has a core speed approaching 3 Ghz with at least two cores, and no less than 4 GB of ram, with integrated graphics (and a reasonable bus). More ideally, and still in budget land, I'd aim for something that has 4 cores clocking at about 3 Ghz, 8 - 16 GB of RAM, and that a discrete AMD/ATI or Nividea video card that retails for about $120 (but is included). Beyond that it would be nice to have a SSD for speed, and you could add an $100 OEM hard disk for bulk storage / backups.
Once you get much above those specs, unless you're a hardcore gamer, are doing something like editing (not just playing) a large amount of HD video, compiling really big source code trees in C++, or trying to number crunch mind bogglingly large data sets, you're firmly in overkill land.
That 8 core, 3.5 Ghz monster, with 64 Gb of RAM, and that $500 video card is likely to sit with most of it's cores 99% idle 90+ % of the time, except when you play a game that may hammer one or two of those cores. Even with that game loaded, all of the programs you normally use in memory, and the OS caching everything it can think of, you'll still probably have a whack of free memory.