as long as your using a high quality modern yeast there should be no need for specialized starter equipment, the advantage to even using a starter is considered by some marginal at best as long as your yeast is healthy. A sanitized cup full of lukewarm water or starter solution will work just as well as any fancy flask does.
The only major thing I worry about with pitching my yeast is to make sure that the wort is cooled enough (I made that mistake once and it delayed the onset of fermentation and I got all sorts of off flavors), but as you say you have a chiller that shouldn't be an issue.
Some form of fermentation temperature control is probably the place you'd see the most gain, particularly if your basement (or wherever you store your fermenter) is a few degrees outside your target temperature.
*EDIT* As for a turkey fryer or other large apparatus for doing your brews, they could potentially speed up the intital heating but they may not justify the expense. I personally just use the Propane burner on the side of my grill and that works just fine. *EDIT*
As I understand it the main draw for doing a full 5 gallon boil is that it allows you to get a brew with extraordinarily high bitterness.
As it was explained to me with regards to Alpha Acids, your boil follows basic rules of solubility, meaning you can only dissolve so much of the Alpha Acids from the hops into solution before no more will dissolve, thus with a 2.5 gallon boil, no matter how much hops you add there is a "cap" as to how much the boil will extract. By increasing the water in your pot to 3.0 gallons, or even 5 you allow more Alpha Acids to enter your brew, giving you more bitterness. That said, for most brews that level of bitterness is undesirable and a 2.5 gallon boil is sufficient for achieving the bittering called for by 99% of the recipes out there excluding a few Imperials or other specialties.
IMO dont even worry about doing AG recipes yet. By and large they add an unnecessary level of complexity. IMO a partial grain is the way to go, using a can of munton's (or other supplier) gives you a solid base of fermentables (reducing the chance of something going wrong) while you still use specialty grains to impart desired characteristics and flavors.
I take most of this from "The Complete Joy of Homebrewing" by Papizan its a few hundred pages of solid advice and recipes that everyone should read.
Even if your no longer a "beginner" the book is divided into various levels of detail, the first section being for the beginner with the final sections basically requiring an Undergraduate degree in Cellular biology to fully understand
While this book was published some years ago, and our fellow homebrewtalkers have discovered more modern changes to the brewing formula, everyone has their opinions and they often conflict, and sometimes those conflicting opinions are each partially right but for different reasons, so take everything you read on the internet with a grain of salt.
