If you basically want a blasty conjurer, I'd opt out of Evocation completely, as per [MENTION=85158]Dandu[/MENTION]'s suggestion. Conjuration is probably the most varied and possibly the most powerful school of magic. It contains lots and lots of blasting spells, some of which are basically just like Evocation spells (e.g. Acid Breath is a Fireball, but with a cone-shaped area and acid damage; everything else is just the same). Some are arguably better, if more specialized, e.g. the Orb spell line (single-target d6/lvl blasts that don't allow save or SR, plus inflicting a short-term condition).
So why not skip Evocation completely already? A conjuration-specialized wizard can do it all, really, and Focused Specialist is actually a strong option for them. One of the benefits is that you only have to spend feats on one area of expertise. A feat lineup of Spell Focus: Conjuration, Augment Summoning, Sculpt Spell, Cloudy Conjuration and maybe a reserve feat will serve you well, and define the character well into the mid levels. Add in the Abrupt Jaunt ACF and you have one powerhouse of a character. For PrC choices, well, Master Specialist immediately comes to mind. Summoning-focused characters also do well with a level or two of Paragnostic Apostle, and of course, Malconvoker is a natural choice for such a character (but requires a bit more investment).
I've seen a build very similar to this in play, and it has impressed me time and again with its versatility and the sheer number of neat little tricks it can pull off.