This plugins are awesome.  They are very CPU and RAM light, which is great on older machines.  They have an OS interface (basically it uses Windows or Mac's look a bit).  Some criticize them for being not the prettiest, but they are very easy to use while still giving you control over almost everything.  They can be both surgical and warm.  (If you have REAPER you won't need these, unless you want them for another app).

ReaPlugs site